Every gun collector has a pet passion, a particular niche where he or she feels most at home. Gordon Herigstad’s passion was the Colt Thompson submachine gun, however, unlike most collectors, Herigstad did the community of collectors a big favor he wrote down everything he knew about Thompsons and published it. At two volumes, 2,200 pp. and weighing nearly 20 lbs., Colt Thompson Submachine Gun Serial Numbers & Histories is the Thompson story’s magnum opus. The bulk of the work is an examination of each and every one of the serial numbers for all 15,000 Colt Model 1921s made during its production run. Every page seems to have something of interest, whether it is a listing of a sale to your local police department, the USMC or to Irish rebels. The second volume centers on more detailed descriptions of the larger contracts and an index of persons, police departments, counties and just about any other entity where a Thompson may have been shipped. Spread throughout both volumes are color reproductions of original Auto-Ordnance correspondence as well as period photos, catalogs and user manuals detailing the wide variety of Thompson tools and accessories. 2200pp.