The book starts from the basics, covering basic concepts such as why estimation and planning is needed, and why should we do size estimation before estimating the effort and duration for any project. It links these basic concepts to the agile approach of: Working as one team, in short iterations, delivery in each iteration, focus on business priorities, inspection & adaptation.
After covering these basics, the book goes into the details of Story Points, Ideal days, Velocity and Planning Poker estimation method. Mike Cohn also explains why estimating and tracking Story Points is better than Ideal days.
The other interesting topics of this book include Prioritisation, Release Planning Essentials, Buffering (concepts seem to be derived from Theory of Constraints), and Tracking Velocity.
The book ends with a case study on "Bomb Shelter Studios" case study, which illustrates the concepts in practice, without getting into too many details.