This publication chronicles the understanding, controlling, and impacts of mountain pine beetles (MPB) central to the Black Hills of South Dakota and Wyoming from the time they were described by Hopkins in 1902, through the presentation of data from work started by Schmid and Mata in 1985. The differentiation of western bark beetle species is discussed and how the final species designations of MPBs and western pine beetles (WPB) came about. This publication strives to synthesize a large portion of the information produced in the last 115 years on MPBs and provide this context for informing, planning, and executing forest treatments to produce MPB resilient forests. In addition, it tells an intriguing and fascinating story about bark beetles and the people who tried to understand and control them.