"Little Pictures of O. Henry" by Arthur W. Page
"The Knight in Disguise" by Nicholas Vachel Lindsay
"The Amazing Genius of O. Henry" by Stephen Leacock
"O. Henry–An English View" by A. St. John Adcock
The Misadventures in Musical Comedy of O. Henry and Franklin P. Adams
"O. Henry in his Own Bagdad" by George Jean Nathan
"O. Henry–Apothecary" by Christopher Morley
"O. Henry" by William Lyon Phelps
"About New York with O. Henry" by Arthur B. Maurice
"O. Henry and New Orleans" by Caroline F. Richardson
"A Yankee Maupassant"–A Summary of the Early Criticism
"O Henry's Short Stories" by Henry James Forman
The O. Henry Index