e-Books Websites

American Institute of Mathematics website where you can download free Mathematics e-books. Their aim is to advance mathematical knowledge through collaboration, to broaden participation in the mathematical endeavor, and to increase the awareness of the contributions of the mathematical sciences to society.
This is a portal that claims to have over 2,400,000 downloadable e-books (PDFs).  It has a keyword search engine plus a broad subject category listing.  Search listings are limited to 100 titles so precise keyword searches should be used.  Due to the size of the full-text books, downloading can be time consuming especially if there is limited bandwidth.
Bookboon.com is the world’s largest publisher of online educational literature. We provide free textbooks for university students, premium eBooks for business professionals and learning solutions for companies.
Open Library is a catalog which provides over 20 million records and access to 1.7 million scanned versions of books, ever since the project began in November 2007 and has been inhaling catalog records from the biggest libraries in the world. It creates link to external sources like WorldCat and Amazon and get users as close to the actual document of their searches.
Freebookcentre.net contains links to thousands of free online technical books. Which Include core computer science, networking, programming languages, Systems Programming books, Linux books and many more.This portal focuses primarily on academic material.  It has a keyword search tool and also a list of broad subject categories
InTech is a pioneer and world's largest multidisciplinary open access publisher of books covering the fields of Science, Technology, Medicine, Engineering, Health Sciences, Life Sciences, Social Sciences and Humanities. Since 2004, InTech has collaborated with 87550 authors and published 2442 books and 6 journals with the aim of providing free online access to research. With +47 million book chapters and journal articles downloads up to date.
Free Information Technology books for downloading.

Living Books About Life is a series of curated, open access books about life -- with life understood both philosophically and biologically -- which provide a bridge between the humanities and the sciences. Produced by a globally-distributed network of writers and editors, the books in the series repackage existing open access science research by clustering it around selected topics whose unifying theme is life: e.g., air, agriculture, bioethics, cosmetic surgery, electronic waste, energy, neurology and pharmacology.

The Academy grants free and downloadable access to all the PDFs of their e-book publications.  Individuals must register for this feature (free).  The initial screen has a key-word search engine plus links to broad categories including Agriculture, Biology and Life Sciences, Energy and Energy Conservation, Food and Nutrition and Health and Medicine.  Each category has a sub-topic list.
Bookshelf provides free online access to books and documents in life science and healthcare. Search, read, and discover.  Access is via keyword search or Browse Titles or New Releases.  In the keyword search tool, other access options (limits) include Subjects, Types and Publishers.  Search results contain the PDFs of books, collections, databases, documentations and reports.
Open Access Textbooks: A FIPSE grant project  ...creating a model for open textbook implementation
Open textbooks are real, complete textbooks licensed so teachers and students can freely use, adapt, and distribute the material. Open textbooks can be downloaded for no cost, or printed inexpensively.
The Oxfam website provides free easy access to over 3000 development and humanitarian policy, training, and research publications from Oxfam and its partners worldwide.
Springer Open publishes a wide selection of open access books across various disciplines. It contains over 200 thousands e-books freely accessible and downloadable.
An index of books which can be previewed or read for free online.
Online book page is an e-book website contains myriad of books in various disciplines. It facilitates access to 20,000 books that are freely readable over the Internet. The site is hosted by the University of Pennsylvania Libraries.
Open books are publishes high quality books by scholars who are committed to making high-quality research available to readers around the world. It publishes monographs and textbooks in all areas, and offers the academic excellence of a traditional press, with the speed, convenience and accessibility of digital publishing. All books are available to read for free online and are also downloadable.
Open textbook collection covers ebooks in different disciplines with a peer review process by faculty in support of open education.
An open educational resources hub that grants free access and adaptation to peer-reviewed books for higher education students and teaching staff.
Open Educational Resources Commons enable access to free, adaptable, open-licensed textbooks and other supplemental resources. It covers sciences(pure and applied), law, education, arts and humanities.
Collection of open access textbooks provided by the University of South Florida.
African minds is an open access publishing platform which publishes ebooks and other publications mainly in social sciences and related disciplines by African authors and organizations.