Captain Charles Tracy, Pistol Instructor to The King's Own Royal Lancaster Regiment, The School of Musketry, Bisley, wrote two instructional manuals during the WWI era, and was an uncredited author in the Revolver section of the British Musketry manual.
Of his books, this is the most complete. Faithfully transcribed by Kirk Lawson, it goes in depth for a variety of subjects ranging from caliber, dry fire, safety, cover and concealment, and methods of training.
This book is a must-have for WWI historians, combat handgun historians, and revolver aficionados.