This superb series of photographs can be found in the wonderfully titled 1917 publication Physical Training for Business Men by American author Harrie Irving Hancock. The book's premise is that a certain quality of physical presence, "impressive carriage and appearance", are essential to "those who would succeed in the business world". This is not, however, all about pure athleticism. Despite his strength and endurance the athlete "may show many signs of bodily slovenliness" which would negatively effect his business dealings. More important than brawn is to foster "the appearance of physical ease, alertness, grace, and discipline." It is these qualities which Hancock promises to build through the exercises shown, a mixture, so he tells us, of those used in the military and certain martial arts.

Though the text is oddly compelling at times, it is the accompanying photographs that really standout. Taken by a "Mr Phelan" (who worked with Hancock on a number of other exercise books) they ingeniously make use of slow shutter speeds, and in some cases multi-exposure, to illustrate the movement of the particular exercise. Their functional value aside, this mix of austere poses and trails of motion blur make for wonderful and curious images. And novel too. According to Hancock, the "method of making these unique examples of camera work is Mr. Phelan's own invention now first set before readers." Four years earlier Swedish gymnast Theodor Bergquist published his Swedish House-Gymnastics (1913) which makes use of multi-exposure photographs to illustrate movement but not Phelan's trails of motion. Exactly how Phelan achieved the effect he does is not always clear, and though certainly the natural blur of slow shutter speeds seems to be involved it's also possible some of the trails were created, or at least significantly enhanced, in the darkroom afterwards. Whatever the method, the effect is marvellous.

The author Harrie Irving Hancock was best known for his many stories ("Boy's books") for children and juveniles, which often displayed a patriotic bent, and in particular for his 1916 four-book series The Invasion of the United States, which imagined the United States invaded by Germany in 1920–21. The popularity of the series is considered by some to have helped shift public opinion towards the United States getting involved in the First World War. Hancock was also an early Western expert on Jiu-Jitsu, and his The Complete Kano Jiu-Jitsu, co-authored with Katsukuma Higashi and originally published in 1905, is still in print today.