The Young People’s Library was published with four different formats between 1895 and 1933. The most common of the formats is #3 which was published between 1902 and 1923.
Today I am adding a third variant cover of Book #44 Alexander the Great to Format #3 of the Young People’s Library.
Distinguishing the earliest from the latest edition should be relatively easy if you look at the ads and follow the simple rules on the website: http://henryaltemus.com/series/series202F3.htm
Exception: If Vic is not listed but the endpapers have the reading girl, the book is a 1902 book with earlier advertisements. This book has a reading girl in the center of the endpapers with no Vic in the ads. This is the one exception to the “Vic” dating. See website.