The HathiTrust contain books out of copyright (pre-1928 for the most part).
Because the University of Missouri - Columbia is a Hathi member,
you can then download parts or all of a book if you prefer to read it off-line. Use the Login In button in the top right and enter University of Missouri - Columbia
as your institution and enter you pawprint after you are redirected to the UM Proxy Server.
You can read the book online as well, and there is full-text search capability.
The slide show below walks you through the process.