The Harvard Classics, originally known as Dr. Eliot's Five Foot Shelf, is a 51-volume anthology of classic works from world literature, compiled and edited by Harvard University president Charles W. Eliot and first published in 1909.
Eliot had stated in speeches that the elements of a liberal education could be obtained by spending 15 minutes a day reading from a collection of books that could fit on a five-foot shelf. (Originally he had said a three-foot shelf.) The publisher P. F. Collier and Son saw an opportunity and challenged Eliot to make good on this statement by selecting an appropriate collection of works, and the Harvard Classics was the result.
All are in the public domain. Finding good compilations is hard, but I've done it for several of the 51 volumes.
In case you want to put in some legwork, I have some of them up here: http://static.bobbymartin.name/Calibre%20Library/
Here are the paths:
Calibre Library/Bibliobazaar/Harvard Classics 01B - John Woolman (138)
Calibre Library/Plato/Harvard Classics 02A Euthyphro; The Apol (48)
Calibre Library/Charles Darwin/Harvard Classics 04 (125)
Calibre Library/Eliot, Charles W. (Charles William), 183/Harvard Classics 04 (245)
Calibre Library/Eliot, Charles W. (Charles William), 183/Harvard Classics 06 (247)
Calibre Library/Charles Darwin/Harvard Classics 07 (244)
Calibre Library/Charles Darwin/Harvard Classics 07 (243)
Calibre Library/Virgil/Harvard Classics 13 - Aeneid (38)
Calibre Library/Eliot, Charles William, 1834-1926/Harvard classics 33,34,__ (246)
Calibre Library/Eliot, Charles William, 1834-1926/Harvard Classics 33,34,__ (248)
Calibre Library/Charles William Eliot/The Harvard Classics (188)
Calibre Library/Unknown/The Harvard classics The Apol (127)
Calibre Library/Unknown/The Harvard classics New Atla (126)
If not, wait a few weeks and I'll probably have them organized and more easily accessible here: http://www.harvardclassics.net/