There are growing sources for electronic versions of books online. You can browse these sources below.
Creative Commons e-books are not in the public domain. They are published with a license that specifies what you can do with them. You are allowed to use them without permission and without any charge, but you must follow other specified restrictions, which are explained here:: http://creativecommons.org/licenses/
Be careful of using any work with ShareAlike license, because often we cannot abide by its requirements. Faculty contracts and SUNY rules stipulate that faculty retain copyright to the courses they create, and that would violate the ShareAlike license. It's ok for things made by students and professional staff as long as you put a CC ShareAlike license on it.
Please note: If you need to request accommodations with content linked to on this guide, on the basis of a disability, please contact Disability Services by emailing them at Disability.Services@esc.edu. Requests for accommodations should be submitted as early as possible to allow for sufficient planning. If you have questions, please visit the disability services website http://www.esc.edu/disabilityservices.