The Book is for anyone who works with data, but it will best suit mixed data teams. Mixed means you have a developer, an analyst (optionally DBA/IT), and product. Those teams will benefit from all of Redash's features.
This book is intended for novices to intermediate-level Data Analysts and Developers.
Although as prior knowledge – nothing is really required, to get the most of the book you need to be fairly familiar with SQL syntax, as some linux knowledge is a great advantage.