With time on my hands these past couple of weeks, I read two short but interesting technical books. The first What every web developer should know about http packs a lot of fundamental knowledge into a very small set of pages. The second OAuth 2.0 distills a complex topic down to even fewer.
Both books were a refreshing antidote to the typical monolithic monster that is commonplace amongst technical literature. By sticking to such small page counts, they focus on the meat of the topic and avoid chewing the fat.
Of the two, OAuth 2.0 is the more practical guide. It explains all of the concepts and flows concisely, and provides a handy pdf cheat sheet to download and stick on the wall next to your desk.
What every web developer should know about http is more about the conceptual knowledge of http. Knowing which will help in other more practical endeavours, such as building a website or api.
On top of the small size, both books are also inexpensive to purchase on an Amazon Kindle. I can recommend them both.