This is a 10-volume set of children's literature, intended as a young person's counterpart to the Harvard Classics series. The first edition was published in 1912 by P. F. Collier and Son. Another edition was published in 1918. Both editions were edited by William Patten, who was also the editor of the Harvard Classics. (There were later Junior Classics sets edited by others, with different selections, but those are still under copyright.)
HathiTrust and the Internet Archive have various page image formats for all volumes. Project Gutenberg has transcriptions of most of the volumes as well, and some audio readings are also becoming available. Except where noted, the volumes below are from the 1918 edition, or a later reprinting of that edition.
This is a "meta-book", which stitches together separate files elsewhere on the Web as they appeared in a previously published book. It is subject to removal if someone produces an integrated edition. If that happens, The Online Books Page will point to the integrated version.