author
b. 1885
Best known for a firsthand history of the 116th Battalion in France, this World War I writer drew directly on his own service as a Canadian battalion adjutant. His surviving work has the feel of a soldier's memorial as much as a military chronicle.
E. P. S. Allen is identified in library and public-domain records as Evelyn Prestwood Seymour Allen, born in 1885. He is chiefly remembered for The 116th Battalion in France (1921), a history of the Canadian Expeditionary Force unit with which he served during the First World War.
Contemporary and archival records describe him as the Adjutant of the 116th Battalion, and military-history sources note that he also served for a time as a company commander. In the preface to his book, Allen says he compiled it from the battalion's official war diary and from his own memory of two years of service, aiming to preserve the battalion's battles, friendships, and losses for veterans and their families.
Reliable biographical detail beyond that is limited in the sources readily available online, so the clearest picture is of a veteran-author whose book stands as both a unit history and a personal act of remembrance. No suitable verified portrait could be confirmed from the sources found.