Between 1940 and 1945, Diamond T Motor Car Company supplied just over 50,000 vehicles to the US military, and also to the Allies. Of this, just over 30,000 were heavy 4-ton 6x6 trucks of varying types: cargo, tow truck, pontoon carrier, engineer, cartographic, etc. The "Diamond" would serve in all theaters of operations, wherever its robustness and reliability were necessary to complete the mission. Due to its expertise, Diamond T also produced the famous half-track, with more than 10,000 manufactured. All of these models are described in this work by Didier Andres, an expert in the subject. The text is illustrated throughout using archival and period photographs and diagrams.