At the Toronto Public Library The Arthur Conan Doyle Collection, one of the most important
Doyle and Doyle-related collections in the world, has added a copy of The Angel of Mons: A First World War I Legend.
Conan Doyle and his family appear in five chapters in the book. Three feature Conan Doyle’s brother in-law, Captain Malcolm Leckie, RAMC. Sherlock Holmes appears in two.
Two official notices about Dr. Malcolm Leckie
Dr. Malcolm Leckie, Battalion, Royal Fusiliers. Royal Army Medical Corps. 
Supernumerary Captain, Restored to the establishment. Returned in February. 1914
Daily Chronicle
Malcolm Leckie Burial, after Aug 28, 1914, Register B 202, Plot 1, row B. Grave 1. Frameries Communal Cemetery. Age 34.
8 December, 1914. DSO. First British Medical Officer to die in the war
London Gazette
The Joseph M. Bruccoli Great War Collection in the Ernest F. Hollings Collections Library, University of South Carolina has also added The Angel of Mons to the collection.
Four documents are the foundation for the legend.
1) Arthur Machen’s “The Bowmen”,
2) Phyllis Campbell’s account in the Occult Review,
3) “The Angel Warriors at Mons”
including numerous confirmatory testimonies,
Evidence of the Wounded
And certain Curious Historical Parallels
An Authentic Record by Ralph Shirley,
editor of The Occult Review
4) Harold Begbie’s On The Side of Angels (1915)
Several of these are in the collection. The Great War Collection added The Angel of Mons, not because the book is rare, but because it recognizes the library’s resources being put to use.