This book is must have and a must read, if you ever face the problem to convince people that an agile transformation is required and brings lots of benefits. It clearly states the positive effects and relies on a study with four years of data. Besides all the fancy benefits, it also explains in detail how they proved and quantified the data and even explains the scientific methods. There are also real world stories about successful transformations included. Bonus: The last chapter is a fine TL;DR, for the dire situations, when you are in a hurry and need more arguments.