If you want some sample code to implement MVCC, I implemented MVCC in multithreaded Java as a toy example

https://github.com/samsquire/multiversion-concurrency-contro...

First read TransactionC.java then read MVCC.java ( or follow the methods that TransactionC calls)

Here's the relevant headers in the ToC.

11. Atomic Transactions

11.1 KV Transaction Interfaces

11.2 DB Transaction Interfaces

11.3 Implementing the KV Transaction

12. Concurrent Readers and Writers

12.1 The Readers-Writer Problem

12.2 Analysing the Implementation

12.3 Concurrent Transactions

  Part 1: Modify the KV type

  Part 2: Add the Read-Only Transaction Type

  Part 3: Add the Read-Write Transaction Type

 12.4 The Free List

 12.5 Closing Remarks

Good question. I've no idea but if I was the author I wouldn't bother with concurrency, I'd assume single user only and always; a database without concurrency is still perfectly good database so it's hardly making the book title a lie.