For the past 2 years, my work has had a focus on delivering fast experiences on the web. I've also kept an eye on any article, tweet or Meetup that would mention performance. It was a job requirement back then, now it's something I'm quite passionate about.
The Book
Which brings me to this book, Web Performance In Action, by Jeremy L. Wagner. It's a very thorough collection of information on how to develop fast websites, from the best way to load fonts to techniques that cater for HTTP/2.
With my years of experience in this area I can honestly say that this book is more suitable for intermediate developers. If you are a beginner, you will still find plenty of tutorials to follow and implement without much effort - there are enough links to ready made solutions that will suit most scenarios and use cases. For an advanced user, it might be more of the same.
Some Highlights
Right in the first chapters of the book, the author explain how to use Chrome Dev Tools to properly investigate performance issues. To me this was one of the highlights of the book. It's very well explained and give the readers a good set of tools to use throughout the book.
Another highlight was the chapter on Service Workers. With the news that Safari is intending to implement this technology, it's good to see the effort in educating more developers about it.
But most of all, the best chapter in my opinion was the one regarding HTTP/2. It manages to summarize a lot of information in a very easy to read manner. If you never heard of header compression, head-of-line-blocking, or SSL, then this is when you will become familiarized with these terms and understand the improvements this new version of the protocol is bringing the to web.