Pretty much what you expect from a "The Definitive Guide" book - it takes you through installing and using Kafka, how to work with it in production, how the internals work, and a laundry list of operations you might want to perform as an admin and how to perform those operations. It's thorough and complete and yet not overly long. It's more than you get from the documentation on the web, a bit better-written and more comprehensive. Plus, hey, it's free www.confluent.io/resources/kafka-the-definitive-guide/

Definitely recommended if you're getting into Kafka. My team was considering using Kafka for a product and I quickly came to feel like I knew what I was talking about during discussions just from reading the first half of this book. Unfortunately, we decided not to go with Kafka for the project but I finished the book anyway and I'd still recommend it.