Chapter 3, Blockchain 101 - Assets, Transactions, and Hashes, covers the concepts of hashing, blocks, (distributed) blockchains, and the mining process.
Chapter 4, Blockchain 101 - Blocks, Chains, and Consensus, builds on the previous chapter and continues exposing the technical details of different kind of assets, how transactions work, and how consensus is reached among entities in a blockchain.
Chapter 5, Blockchain 101 - Security, Privacy, and Smart Contracts, shows that with blockchain, trust is everything. It also talks about how to know that your assets in a blockchain are secure. In addition to security, it covers how blockchain protects your privacy. Finally, this chapter covers smart ...