Roster of the Regenbogen Division (42nd) under Major General William A. Mann is a detailed documentary book written by Harold Stanley Johnson. In this work, the author examines the composition and structure of an outstanding unit of the American army during the First World War - the Regenbogen Division. The book contains information about the division's leadership, combat operations, military achievements, and the unit's contribution to the U.S. victory. Due to its balanced approach and large volume of documents, Harold Stanley Johnson's book is considered an important source of information on the military history and organization of the American army during the First World War.