From the Houghton Library Blog:
An exciting array of materials have recently been digitized at Houghton. They include manuscript material from Joanna Baillie, George Eliot, John Keats, Charles Lamb, Percy Shelley, Robert Southey, Alfred Tennyson, Hester Thrale and George Washington. A 15th century breviary and Belgian incunable, multiple musical scores, cartoons, broadsides and more may also be viewed fully online.
Houghton Library is the primary repository for Harvard’s rare books and manuscripts. The collections of the Houghton Library focus on the study of Western civilization. Materials relating to American, Continental, and English history and literature comprise the bulk of these collections and include special concentrations in printing, graphic arts, and the theatre