HathiTrust is a partnership of major research institutions and libraries working to ensure that the cultural record is preserved and accessible well into the future. The HathiTrust Digital Library includes millions of digitized book titles, most of which were published before 1923.
Provides free access to more than 33,000 (primarily older public domain) books which can be downloaded in a variety of formats including ePub, Kindle, HTML and plain text.
The OED is widely regarded as the most significant dictionary of the English language, offering the meaning, history, and pronunciation of more than 600,000 words —past and present— from across the English-speaking world.