“If you use Rails and Postgres, this book is required reading.
If you use Postgres and a different framework, you will still get a ton of value out of it. Every section goes deep.”
Thank you @jpcamara! 
www.goodreads.comJP's review of High Performance PostgreSQL for Rails5/5: "The High Performance PostgreSQL for Rails Challenge" - an attempt to read this book without finding something useful in every chapter. Despite having used PostgreSQL for several years, I came away from every chapter with a new insight - usually several. If you use Rails and Postgres, this book is required reading. If you use Postgres and a different framework, you will still get a ton of value out of it. Every section goes deep and you'll glean something new about building with Postgres on every re-read.