The Airframe and Miniature series by Valiant Publications gives the modeler and the enthusiast the most information and details you will find about a given subject.
When you first open the book, you will see the table of contents, then the preface. The preface goes over a brief history of P-51s from the B model up to the K model. There are also lists of USAAF and RAF squadrons that operated P-51s during and after WWII. The preface concludes with a run-down of which countries used the aircraft, how they were acquired and, their operational life.
Chapter one is the evolution of the P-51 from the XP-51D to the P-51K-20-NT. Each version of the P-51 has about a paragraph of information on the differences between models and a side profile.
Chapter two is about the evolution of the Photoreconnaissance, trainers, and projected production versions. With the same layout of chapter one.