The thirty chapters in this long awaited book tell the in depth story of the ingenious half-locked roller action, from the curiously simultaneous development of initial prototypes by two German companies during World War II - the Mauser Gert 06H and the Grossfuss MG42V - right through to the present day. After the war the roller lock was taken first to France, where several hitherto little-known assault rifle prototypes were developed by ex-Mauser engineers in calibres 7.65x35mm French short and 7.62x33mm (.30 US carbine). In 1950 the roller lock moved to Spain, where what became the CETME family of roller-locked weapons was developed by ex-Mauser engineer Ludwig Vorgrimler, initially chambered for the unorthodox 7.92x41mm cartridge. By the mid-1950s the roller lock had returned - Full Circle - to Germany, and a co-operative manufacturing programme had been established between CETME and the fledgling German armsmaking firm Heckler & Koch GmbH, whose pre-adoption prototypes included the 7.62mm NATO calibre H&K STG CETME and the H&K DM3 (CETME) . The finalised G3 rifle was adopted by the Bundeswehr in 1959, and nearly two million examples were produced by H&K and Rheinmetall with fixed, folding and retractable buttstocks. The roller lock action then formed the basis for the H&K weapons family , consisting of numerous models and variations of SMGs, carbines, rifles and machine guns in calibres ranging in power from 9mm Parabellum to - very briefly - .50 Browning! Versions of the G3 and other H&K arms were also sold commercially (we list 25 countries using ready-made H&K product), and manufactured abroad under license. Models made by or for Burma, Denmark, Greece, Iran, Malaysia, Mexico, Norway, Pakistan, Portugal, Saudi Arabia, Sweden, Thailand and Turkey are depicted and described, with clear illustrations of their unique features and markings. Final chapters include an overview of the burgeoning Aftermarket - H&K and CETME.