The Triumph Speed Twin & Thunderbird Bible is a comprehensive guide to all 5T 498 cm³ and 6T 649 cm³ models from 1938 to 1966. Published by Veloce Publishing The Limited in 2016, this trade paperback features illustrations by Harry Woolridge. With a total of 144 pages, this book is filled with information on motorcycles, motor sports, and the history of Triumph bikes. The detailed coverage makes it an essential read for motorcycle enthusiasts and collectors.