I am adding an interesting variant book cover to this series page today. Boys and Girls Own Library

The basic format for this series is the same as Series #58 Boys and Girls Classics. The difference between the two series is that Series #59 was published later- 1909-1910 versus 1899-1906. The later series obviously has later advertisements in the back of the back. Series 59 lists Little Men and Women Series whereas Series 58 does not.

Both series have front cover book appropriate pictures.

This variant book has a picture from the Vademecum Series. This appears to be a mistake by the publisher.
See: http://www.henryaltemus.com/vademecum.htm