Hummer's story began with the HMMWV military vehicle developed by AM General in the 1980s. A civilian version, the H1, went on sale in 1992, and General Motors purchased the brand name in 1999. GM launched the H2 in 2002 and the smaller H3 in 2005, before winding the marque down during its 2009 restructuring. The name returned in 2020 as the GMC Hummer EV, an electric pickup built under the GMC brand.

Hummers are known for extreme off-road capability, stout frames, full-time four-wheel drive with locking differentials and high ground clearance. The H1 kept the military layout with portal axles and optional central tire inflation, while the H2 and H3 used truck-derived GM platforms, offering V8 power alongside the H3's inline five, with serious towing capacity.

Hummer service manuals cover the engine, transmission and transfer case, front and rear differentials including the portal axles of the H1, suspension and steering, brake hydraulics and ABS, air conditioning and complete electrical wiring diagrams. Diagnostic procedures, torque specifications and maintenance schedules are included for each model year. The H3 Alpha paired a 5.3-litre V8 with the smaller body, and H2s tow trailers and boats with ease.

Owners typically handle much of their own maintenance because many Hummers are used off-road far from dealers, so accurate documentation matters. Independent garages, fleet operators and restorers also rely on these manuals to keep H1s and H2s running long after factory support ended.