Harvard Classics (Bookshelf) – Gutenberg
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, that was first published in 1909.
Dr. Eliot, then President of Harvard University, 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.)
Also, from the Internet Archive: The Harvard Classics / Dr. Eliot’s Five Foot Shelf