Update chapters based on community feedback

Revised and expanded content across 9 chapters incorporating feedback
received via X and Telegram DMs. Big thanks to everyone who took the
time to send thoughts, corrections, and suggestions. It genuinely
makes the material better.

ch01 (Bitcoin):
- Added a forward reference to Chapter V at the end of the private keys
  section, directing readers to seed phrases, HD wallets, and the
  tradeoffs between self-custody and custodial services.

ch02 (Ethereum):
- Added a cross-reference to Chapter VIII (MEV) at the end of the
  EIP-1559/fee market paragraph, noting that MEV is the root force
  shaping block production and censorship concerns.
- Added an explanation of proposer-builder separation (PBS) and
  MEV-Boost after the validator/slot/epoch description, clarifying
  that most validators select from builder bids rather than sequencing
  transactions themselves.
- Added a note that centralized rollup sequencers concentrate MEV
  extraction in ways that differ fundamentally from the competitive
  L1 builder auction, with a pointer to Chapter VIII.

ch03 (Solana):
- Added a new paragraph on DePIN as a natural fit for Solana's
  architecture, covering Helium, Hivemapper, and Render, explaining
  why sub-cent fees and high throughput are prerequisites rather than
  nice-to-haves, and detailing Helium's 2023 migration. Includes a
  forward reference to Chapter XIII.

ch04 (L1 Blockchains):
- Added a paragraph placing DA-specific L1s (Celestia, EigenDA, Avail)
  in the modular spectrum as the far end of the unbundling thesis,
  distinguishing them from Ethereum's partial unbundling and
  cross-referencing Chapter II where they are covered in depth.

ch05 (Custody):
- Added a new section on the "$5 wrench attack" and physical coercion
  threats, including documented real-world cases of home invasions and
  kidnappings targeting crypto holders, the attacker's operational
  logic (irreversibility, no institutional override), and technical
  mitigations including the BIP-39 passphrase for plausible
  deniability, Trezor's wipe code, multisig, and time-locked
  transactions.
- Added a new section on inheritance and incapacitation planning,
  covering the core tension between pre-death heir access and security,
  sealed executor instructions, Shamir's Secret Sharing as the
  recommended approach, multisig arrangements for incapacitation
  scenarios, the two most common failure modes (missing passphrase,
  over-reliance on dead man's switch services), and why briefing an
  estate attorney directly rather than relying on standard estate
  language is not optional.

ch06 (Market Structure):
- Expanded the spot trading section to clarify that stablecoins are
  not merely a quoting convention but the settlement layer, dominant
  collateral type, and base currency for every product in the chapter,
  with a pointer to Chapter IX for stablecoin mechanics and Section V
  for systemic risk.
- Added a new subsection "Stablecoin Risk: The Settlement Layer" in
  the systemic risks section. Uses the March 2023 USDC depeg during
  the SVB collapse as a case study showing how a single stablecoin
  stress event simultaneously breaks collateral valuations, funding
  rate mechanics, mark price consensus, and directional hedges across
  every venue at once. Addresses USDT concentration risk and the
  practical leading indicators practitioners should monitor.

ch07 (DeFi):
- Updated the Section V infrastructure intro to clarify that bridge
  vulnerabilities are covered in Chapter IV alongside cross-chain
  architecture, and named the three largest bridge exploits (Ronin,
  Wormhole, Nomad) rather than leaving the reference abstract.

ch08 (MEV):
- Added an entirely new Section V covering MEV on L2s, which was
  missing from the chapter. Includes: the two-sided nature of rollup
  MEV (no public mempool eliminates sandwiching bots but centralizes
  ordering power); the named operators of major sequencers as of early
  2026 (Offchain Labs for Arbitrum, OP Labs for Optimism and Base,
  Matter Labs for zkSync, StarkWare for Starknet); the sequencer's
  structural MEV advantage including self-insertion and latency
  asymmetry as a payment-for-order-flow analog; current fair ordering
  commitments (FIFO policies) and why they are trust-based rather than
  protocol-enforced; based sequencing as the trust-minimized
  decentralization approach and its latency tradeoff; shared
  sequencing networks (Espresso Systems, Astria) and how they enable
  atomic cross-rollup composability; and an honest assessment of user
  protections on L2 today versus L1.
- Renumbered the former Section V (Cross-Domain MEV) to Section VI.

ch15 (Prediction Markets):
- Added a detailed new subsection "The French Whale" covering the Theo
  case from the 2024 election cycle: his background as a former bank
  trader, the $80M position spread across 11 accounts as a standard
  large-order execution strategy, the neighbor polling methodology he
  commissioned from YouGov in swing states, the manipulation debate
  and Polymarket CEO Shayne Coplan's defense, Chainalysis's estimate
  of $78.7M in net profit, and the unresolved tension between the
  information aggregation thesis and the market's vulnerability to a
  single well-funded actor imposing a wrong prior on the price.
- Rewrote the "Manipulation and Market Depth" subsection to use the
  Theo episode as a concrete anchor, replacing generic language with
  specific observations about market depth, liquidity, and the
  distinction between a whale who was right and the structural
  vulnerability that exists regardless of the outcome.
- Tightened the description of the manipulation accusation against Theo
  to remove redundant phrasing.
- Strengthened Coplan's two-sided market defense by making explicit
  that a whale pushing price away from fair value is offering other
  traders an attractive bet and risking a large loss, not exercising
  costless influence.
- Rewrote the closing paragraph of the Theo section to sharpen the
  unresolved concern: the real risk is not that a whale can permanently
  dictate price, but that a relatively thin market can display a
  distorted price signal for days before opposing capital corrects it,
  and media outlets treating those odds as authoritative is the actual
  vector of harm.

Author: lawmaster10

Chapters/ch01_bitcoin.md

@@ -66,7 +66,7 @@ Bitcoin operates on the same principle. Your wallet holds a collection of UTXOs,
 
 Every full node independently maintains its own view of this global UTXO set, the complete collection of all spendable outputs, by validating the entire blockchain. Ownership of these UTXOs is controlled by **private keys**, extremely large random numbers (roughly between 1 and 2²⁵⁶, about 10⁷⁷ possibilities) that function as the cryptographic secret proving control over funds. Your wallet generates these from high-quality randomness, similar to flipping a fair coin 256 times and treating the sequence of heads and tails as a 256-bit number. The private key is the core secret in Bitcoin: it lets your wallet produce digital signatures that satisfy the spending rules on your UTXOs.
 
-Put simply: you “own” bitcoin if you control the private keys needed to spend specific UTXOs. If you lose those keys, those coins are effectively gone. If you keep them safe, only you can move those coins.
+Put simply: you “own” bitcoin if you control the private keys needed to spend specific UTXOs. If you lose those keys, those coins are effectively gone. If you keep them safe, only you can move those coins. The practical question of *how* people actually back up and manage keys (mnemonic seed phrases, hierarchical deterministic wallets, and the tradeoffs between self-custody and custodial services) is covered in depth in Chapter V.
 
 The rules for spending these UTXOs are defined by **Bitcoin Script**, a simple programming language. Each output includes a locking script that sets the spending conditions. Think of it as a lock that specifies what key is needed. When someone wants to spend that output, they provide unlocking data (essentially the key) to satisfy those conditions. The Bitcoin network verifies that the key fits the lock before allowing the transaction.
 

Chapters/ch02_ethereum.md

@@ -52,7 +52,7 @@ The most significant innovation is what happens to fees. Of the total fee paid,
 
 During periods of sustained demand, the base fee burn can exceed new ETH issuance from staking rewards, making the overall supply net deflationary (shrinking rather than growing). Higher network usage increases the burn rate, tightening supply and potentially supporting ETH's value. Since The Merge in September 2022, there have been extended periods where ETH supply has been deflationary. However, upgrades like Dencun and EIP-4844 also made L1 gas cheaper, which in turn reduced fee burn. Since 2024 there have been periods where ETH supply has turned net inflationary again despite the burn mechanism.
 
-EIP-1559 reduced fee volatility and dramatically improved user experience by making fees more predictable. Users can set reasonable max fees without worrying about overpaying, and wallets can estimate costs more accurately. Importantly, this change modified how fees work without altering Ethereum's consensus mechanism (the system went through this upgrade during proof-of-work and kept it after transitioning to proof-of-stake). The upgrade introduced new validation rules that all nodes must enforce, including the base fee calculation algorithm and the burning mechanism. However, it didn't address all fee market concerns. Issues like transaction censorship (validators choosing to exclude certain transactions) remain active areas of research, with proposals like inclusion lists (rules forcing validators to include certain transactions) still being developed.
+EIP-1559 reduced fee volatility and dramatically improved user experience by making fees more predictable. Users can set reasonable max fees without worrying about overpaying, and wallets can estimate costs more accurately. Importantly, this change modified how fees work without altering Ethereum's consensus mechanism (the system went through this upgrade during proof-of-work and kept it after transitioning to proof-of-stake). The upgrade introduced new validation rules that all nodes must enforce, including the base fee calculation algorithm and the burning mechanism. However, it didn't address all fee market concerns. Issues like transaction censorship (validators choosing to exclude certain transactions) remain active areas of research, with proposals like inclusion lists (rules forcing validators to include certain transactions) still being developed. The economic forces driving both censorship and the entire shape of block production today are rooted in **Maximal Extractable Value (MEV)**, the profit available to whoever controls transaction ordering. Chapter VIII covers MEV in depth.
 
 ### How Ethereum Identifies Accounts and Assets
 
@@ -102,7 +102,7 @@ Beyond energy efficiency, The Merge restructured Ethereum's architecture itself:
 
 Ethereum's proof-of-stake system operates like a carefully choreographed dance, with thousands of validators working together in precise intervals to maintain network security.
 
-Time in Ethereum moves in precise intervals: every 12 seconds marks a slot, and every 32 slots (about 6.4 minutes) forms an epoch. In each slot, the protocol randomly selects one validator to propose a new block using a cryptographic seed derived from the previous epoch, while hundreds of others provide attestations, which are cryptographic votes confirming that the proposed block follows all the rules.
+Time in Ethereum moves in precise intervals: every 12 seconds marks a slot, and every 32 slots (about 6.4 minutes) forms an epoch. In each slot, the protocol randomly selects one validator to propose a new block using a cryptographic seed derived from the previous epoch, while hundreds of others provide attestations, which are cryptographic votes confirming that the proposed block follows all the rules. In practice, most validators do not assemble blocks themselves. Because the ordering of transactions within a block is enormously valuable (a point explored fully in Chapter VIII), a specialized ecosystem of **block builders** has emerged to construct the most profitable blocks possible and auction them to proposers via **MEV-Boost**, a widely adopted piece of middleware. This **proposer-builder separation (PBS)** means the validator's job at proposal time is largely to select the highest bid from a builder, not to sequence transactions independently.
 
 The path to **finality** (the point where a transaction becomes irreversible) follows a two step process. First, a block becomes justified when it receives attestations from at least two thirds of validators. Then, in the following epoch, if another supermajority confirms that justification, the block becomes finalized. This process typically takes about 12.8 minutes. After finalization, reversing a transaction would require coordinated attacks triggering severe financial penalties called **slashing**, which scale with the number of validators involved.
 
@@ -170,7 +170,7 @@ The advantage over optimistic rollups is compelling. ZK rollups avoid the week l
 
 Beyond the core differences between optimistic and ZK approaches, several other dimensions matter when evaluating rollups.
 
-In practice, most rollups currently rely on centralized sequencers to achieve the fast confirmations users expect. Unlike Ethereum mainnet, which distributes block proposal across thousands of validators, these rollups use a single entity to order transactions and produce blocks. While this represents a temporary engineering choice rather than a permanent design, it introduces potential censorship risks and single points of failure. Leading rollups are actively developing solutions to eliminate sequencer centralization while preserving performance. Shared sequencing networks distribute ordering responsibility across multiple parties, creating redundancy without sacrificing speed. Sequencer rotation systems periodically change which entity handles transaction ordering, preventing long-term control by any single party. Inclusion lists require sequencers to include certain transactions within specified timeframes, making censorship more difficult. Preconfirmations allow sequencers to make soft commitments about transaction inclusion before formal consensus, improving user experience while maintaining reversion options through slashing mechanisms and dispute windows.
+In practice, most rollups currently rely on centralized sequencers to achieve the fast confirmations users expect. Unlike Ethereum mainnet, which distributes block proposal across thousands of validators, these rollups use a single entity to order transactions and produce blocks. While this represents a temporary engineering choice rather than a permanent design, it introduces potential censorship risks and single points of failure. It also concentrates MEV extraction: a single sequencer controls transaction ordering across the entire rollup, capturing profits that on Ethereum mainnet are competed over by many independent builders (Chapter VIII explores this dynamic). Leading rollups are actively developing solutions to eliminate sequencer centralization while preserving performance. Shared sequencing networks distribute ordering responsibility across multiple parties, creating redundancy without sacrificing speed. Sequencer rotation systems periodically change which entity handles transaction ordering, preventing long-term control by any single party. Inclusion lists require sequencers to include certain transactions within specified timeframes, making censorship more difficult. Preconfirmations allow sequencers to make soft commitments about transaction inclusion before formal consensus, improving user experience while maintaining reversion options through slashing mechanisms and dispute windows.
 
 Proof systems continue to evolve in maturity and coverage. Many ZK-rollups still operate with "training wheels" (additional security mechanisms that can pause or override the system during early phases while the technology matures). Optimistic rollups depend on robust fault proof systems that are still being refined and battle-tested. Fee structures combine L2 execution costs with L1 data availability and inclusion fees. Additionally, rollups operate in different data availability modes. True rollups post all data to Ethereum, while validiums use external data availability or hybrid approaches that trade cost savings against stronger trust requirements.
 

Chapters/ch03_solana.md

@@ -286,6 +286,8 @@ The upgrades detailed in Section III aim to close this gap. Alpenglow's sub-200-
 
 Beyond trading existing crypto assets, products like xStocks are bringing tokenized equities directly to Solana. These synthetic representations of traditional stocks trade on-chain with Solana's settlement speed and composability advantages. Liquidity, price discovery, and speculative attention are consolidating toward a single chain that offers faster settlement, better UX, and denser capital concentration. This represents Solana's case for bringing capital markets on-chain: not replacing traditional finance infrastructure, but offering an alternative venue where the same assets can trade with different properties.
 
+DePIN (Decentralized Physical Infrastructure Networks) represents another natural fit for Solana's architecture. Networks like Helium, Hivemapper, and Render coordinate millions of micro-transactions from physical devices (wireless hotspots, dashcams, and GPUs) where sub-cent fees and high throughput aren't nice-to-haves but prerequisites. Helium's migration to Solana in 2023 validated this, moving its entire proof-of-coverage and reward distribution system onto the network. The account model, state compression (critical for networks tracking hundreds of thousands of devices), and atomic composability make Solana the default settlement layer for most major DePIN projects. Chapter XIII explores the DePIN model, its economics, and its challenges in depth.
+
 ### Limitations and Trade-offs
 
 Despite these strengths, Solana's architecture creates clear trade-offs that favor certain applications over others. Projects prioritizing maximum decentralization over performance might prefer an L1 with a more distributed validator set and lower hardware barriers. Solana's Rust-based development environment also remains less familiar to developers who learned on Ethereum's Solidity, though the Anchor framework significantly lowers the learning curve.

Chapters/ch04_l1_blockchains.md

@@ -60,6 +60,8 @@ While vertical scaling pushes individual chains to process more transactions (co
 
 Instead, Ethereum pivoted to a rollup-centric model: L2s provide the parallelism and handle most user transactions, while the L1 focuses on settlement and data availability. Through blob transactions (EIP-4844, covered in Chapter II) and planned future upgrades, Ethereum spreads rollup data across validators rather than splitting execution into separate shards. This exemplifies how separated layers can optimize independently while coordinating through well-defined interfaces.
 
+Ethereum's evolution stops short of full unbundling: it still handles consensus, settlement, and DA together, with execution pushed to L2s. Some projects took the modular thesis further by building entire standalone L1 blockchains dedicated exclusively to the data availability function. Celestia, which effectively coined the "modular blockchain" framing, is itself an L1 that provides consensus and DA only, with no execution layer at all. EigenDA and Avail pursue similar specialization through different trust models. Because these DA-specific chains are covered in depth in the context of Ethereum's rollup ecosystem (Chapter II), they receive only this brief mention here; the key point for this chapter is that they represent the far end of the unbundling spectrum: L1s whose entire design is organized around one of the four planes rather than bundling all of them.
+
 #### Alternative Approaches to Specialization
 
 Other ecosystems pursue specialization differently. Avalanche scales through a subnet architecture where independent, application-specific blockchains run in parallel, each with its own set of validators selected from a larger validator pool. Unlike systems where all chains share the same security, subnets operate independently and can customize their own rules, including which virtual machine to use, what token to charge for fees, and how governance works.