While it is perhaps impossible to produce a definitive history of the Class 47 in one volume, this book gets close to achieving such an ambition. The Brush Type 4 (later Class 47/48) was the single largest type of main-line diesel-electric locomotive to be constructed by British Railways, with 512 being built at Crewe Works and at Brush's Falcon Works at Loughborough between introduction in 1962 and the end of production five years later. Allocated to all BR regions, with the exception of the Southern, the class was to see widespread use on a great variety of traffic, from top-link passenger expresses to more mundane freight workings. Over the 50 years since the type's introduction, the class has been subject to much modification and a great variety of livery has been carried, particularly in the years since Sectorisation and Privatisation.Up to 1986 only five examples of the class had been withdrawn, all the result of accident damage, but from the end of that decade, and especially since Privatisation and the arrival of the now-ubiquitous Class 66, there has been a slow but inexorable decline in the class's numbers, although a quantity of both Class 47 and modified Class 57 types remain in main-line service. A significant number are also now entering preservation. This book marks the 50th anniversary of the class and is the result of many years of detailed research in the archives, rewriting much of the accepted wisdom of the type's history.