It's reasonable to look over the description of this book and ask yourself what is so idiosyncratic and bizarre about SQLite that it merits a 464-page reference for developers to wrap their heads around it. Especially when as a stated goal, SQLite overtly aims to be simple, stripped-down and uncomplicated in use.
The answer thankfully, is not very much. As the author goes to great pains to reinforce many times, SQL as a logical Data Manipulation Language is specified as being completely divorced from the underlying implementation. While all SQL DBs have their own annoying extensions, incompatibilities and divergences from the standard, the underlying syntax and form of SQL is mostly constant. You may, in the course of reading this book, come under the impression you're actually reading two separate publications, with their chapters collated together and coarsely interleaved in the same binding. One is broadly about SQL and RDBMS's, the other is actually about SQLite. As it turns out, there isn't much specific to the topic of SQLite that really demands so much coverage, so with the declared intention of being "definitive", the author has written something of a ground up tutorial/reference that aims to introduce both SQL and SQLite to audiences thoroughly unfamiliar with either. Passing over the table of contents in the front of the book I found myself raising an eyebrow as I realized how narrow of a demographic this book aims to cater to; that is, programmers who know nothing of SQL or relational DB theory and yet feel compelled and ready to embed an RDBMS library into their applications. I happened to be one of these people, but I question the usefulness of much of this book to someone already familiar with SQL.
Chapters 1 and 2 are boilerplate for introducing and setting up SQLite. Chapter 3 is an interesting but non-particular explanation of the Relational model. Chapter 4 is the centerpiece of the book and is a thorough introduction to SQL; while SQLite obviously is chosen as the reference implementation here, apart from the usual nuances this should not be at all unfamiliar to users of other relational DB's.
It isn't until chapter 5 that the book veers into territory solidly in the realm of SQLite. Chapters 5,6,7 and 8 all concern programming language interfaces to SQLite, however there's questionable utility to some of this. Chapter 5 "Design Concepts" redundantly presents the general structure of the API in pseudocode in advance of chapter 6 doing it all over again with the actual C function calls. 7 is the extension API, then chapter 8 continues over to the interfaces to higher level scripting and RAD languages. The repetition in this chapter is somewhat disquieting as unsurprisingly the general process of using SQLite is unchanged regardless of modules or the API in use, and in most languages there are reasonable standard generic DB interfaces to be used and there turns out not to be anything necessarily special about working with SQLite. Nonetheless, it's all there for reference and I found the examples in the Perl section useful while working on a project. The book ends with an overview of the internals of SQLite's compiler and VM backend. It's suggested in the chapter that an understanding of the engine may be of use to an application developer in reasoning about the workings of his or her queries, but I generally suspect that the point at which someone would need to concern themselves with the workings of the internal VM is the point at which they've either reached the performance limitations of their machine or the library, or else they've missed the forest for the trees and need to review the logical organization of their query. The remaining 60 or so pages are all reference appendices.
For programmers already familiar with SQL, most of what you should find of worth here is the API reference. Listings of function calls don't necessarily validate these chapters but the in-depth explanations of locking issues and race conditions do make these parts of the book worth the read versus just looking up the on-line documentation. Despite the criticisms earlier, if you actually fall within the boundaries of whom this book would provide instruction of unfamiliar topics to and need the long explanation of SQL given here, this is a good book for the topics it covers. The general SQL chapters are interesting and highly educational and well written, the SQLite chapters are good reference tutorials, but note that this book aims to be exhaustive and potentially retreads material that will likely already be known to advanced users.