BCcampus Open Education
The B.C. Open Textbook Collection is home to a growing selection of open textbooks for a variety of subjects and specialties. Discover open textbooks that have been reviewed by faculty, meet our accessibility requirements, and/or include ancillary materials (quizzes, test banks, slides, videos, etc.).
 

FreeBookSpot
Free Book Spot is a free e-books links library where you can find and download free books in almost any category. This website  requires users to have an account for content access.
 

Harvard University
Internet Archive: Books sponsored or contributed by Harvard University. This website offers free limited access.
 

Intechopen
Intechopen provides free access of e-books and e-journals within the fields of science, technology, and medicine. This website offers free online reading only.
 

Internet ArchiveThe Internet Archive, a digital library of Internet sites and other cultural artifacts in digital form. Like a paper library, we provide free access to researchers, historians, scholars, the print disabled, and the general public. Our mission is to provide Universal Access to All Knowledge. Need to have account / not downloadable but can be loaned out (online reading) e-books can be borrowed for 14 days.
 

NCBI Bookshelf
National Center for Biotechnology Information bookshelf provides free access to books and documents in life science and healthcare. Supports online reading only.
 

Openlibrary
Open Library is an initiative of the Internet Archive, a 501(c)(3) non-profit, building a digital library of Internet sites and other cultural artifacts in digital form. Other projects include the Wayback Machine, archive.org and archive-it.org. For online reading and some titles can be dowloaded but old copyright year.
 

The Online Books Page
Able to access over 35,000 free ebooks from this site, powered by the University of Pennsylvania. Readable online.