There is a weapon that looms large in the history of arms, one that has largely disappeared from memory: the warhammer. For over 300 years, across Asia, Europe, and even North Africa, the warhammer was the close-combat weapon of choice. The high-tech plate armor of the 14th and 15th Centuries stood absolutely no chance against it. The mass-produced plate armor of the 16th and 17th Centuries fared even worse against what is one of history's most successful weapon designs. Small, almost dainty in appearance, the warhammer lives on today in fantasy, in movies, and games in an imaginary giant, heavy, sledge hammer shape, a form that distorts its true history and its lethal meaning as a small, handy, post-medieval "wonder weapon." In this work, James Roth explores warhammer design, function, and variations of the weapon across cultures. Through discussion of 184 figures, he plots the outlines of a warhammer history and presents the argument that the persistence of this weapon on battlefields was tied to the historical duration of plate armor. Included is a chapter on fencing with warhammers and other chapters on the German Dolchstreitkolben and Polish and Ukrainian horseman's hammers. This is the most complete survey of the warhammer in print today. About the author: James Roth (a pseudonym) fenced competitively at the US regional levels. Ex-infantry, he is a trained bayonet fencer and is a former technical writer specializing in modern weapons systems.