
"The Definitive Guide To Sqlite" deals with computers/software.
By that point most popular stuff has at least one good published book on it explaining it in an accessible way. William S. Vincent's Django for Beginners, Robin Wieruch's Road to React, (a little older) The Definitive Guide to SQLite, and (a little heavier) Haskell Programming From First Principles are all excellent examples of this that I've read cover to cover.
Maybe the only strange thing about my approach is that I generally take notes by making Anki flashcards while I read. I generally like to learn libraries well ahead of whenever I think I might actually use them if possible, and this is the only way a baseline level of information about e.g. Django/React is going to survive in my head for 2 years before I actually finally stumble across something that makes me think, "Hey, this would be a really good usecase for a Django/React project."
And then there is Database Systems, The Complete Book where the second half of the book offers in deep coverage of the implementation of database systems.
If you want a more academic treatment, I would recommend C. J. Date's _An Introduction to Database Systems_.
Also, it's been my experience that books which claim to cover relational databases in general, but which actually assume MySQL throughout, are usually pretty bad.
ObRelational: For people who want to learn about the relational model, two of the better presentations I've read are:
1. The Definitive Guide to SQLite by Mike Owens -- short, non-academic, theoretical enough to be useful. Focuses on SQLite, which is nice, because that way you don't take MySQL's flaws for granted.
2. An Introduction to Database Systems by C. J. Date -- academically thorough; it's a textbook, so the previous edition is pennies on the dollar. Mostly covers the relational model itself, rather than SQL, which is somewhat like comparing the pure untyped lambda calculus to Scheme. Once you understand the big ideas, though, everything else is just syntax and performance tuning (which are often implementation-specific anyway).
I can also recommend Mike Owens' book Definitive Guide to SQLite
http://www.amazon.com/Definitive-Guide-SQLite-Mike-Owens/dp/...