In this new paperback edition, The Triumph Speed Twin & Thunderbird Bible shows the definitive history of Triumph's hugely popular Speed Twin and Thunderbird models. Much more than a simple history, this book is the ultimate single source of detailed information on these two classic Triumph twins - ideal for owners and would-be owners alike. This 'Bible' contains a wealth of information, and covers the models' year-on-year development history from 1938-1966, engine and frame numbers, model type identification guide, colour schemes, complete technical specifications of every model, and details of international sporting achievements attained on these classic machines. In addition, factory photographs show each model in authentic, original detail.