ebooks

BC Campus OpenEd

A Canadian OER initiative provides hundreds of free e-textbooks in various subjects: Economics, Business and Finance, Engineering, Biological and Physical Sciences, Academic Writing, Language Learning, etc. 

Typical e-textbooks from BC Campus:

Open Textbook Library

Developed by University of Minnesota, provides good textbooks on various disciplines including Business, Finance, Computer Science, Engineering, and Social Sciences. A good platform to find textbooks such as "financial mathematics", "organic chemistry lab techniques", etc.

Typical e-textbooks from Open Textbook Library:

OpenStax

High-quality, peer-reviewed, openly licensed college textbooks that are free online including: Calculus, Statistics, Biology and Microbiology, Chemistry, Anatomy, Physics, Macro-Economics, Micro-Economics, Sociology, Psychology, Accounting, Business Management, etc. 

Typical e-textbooks from OpenStax:

IEEE Xplore

IEEE Xplore, provided by IEEE community, includes ebooks, journals and other resources specialized for engineering disciplines

Open Textbook Library

Open textbooks are textbooks that have been funded, published, and licensed to be freely used, adapted, and distributed. These books have been reviewed by faculty from a variety of colleges and universities to assess their quality.