Directory of Open Access Books (DOAB) -Provides access to over 3000 e-books from more than 100 well-known publishers covering almost all disciplines : https://www.doabooks.org/
PDF Drive is a free search engine which allows you to search, preview ,download millions of e-books : https://www.pdfdrive.com/
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The World's largest e book library. : https://b-ok.org/
e books of an Indian Writer in English 10 free e books : https://www.audible.in
Free Book centre contains links to thousands of free online technical books. : http://www.freebookcentre.net/
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The OAPEN Library contains freely accessible academic books, mainly in the area of humanities and etc. : http://www.oapen.org/home
Google books the world's most comprehensive index of full-text books : https://books.google.com
More than 3,000 Open Access e books are now available at no cost to libraries or users. These titles reflect JSTOR’s high standards for quality content and are freely available for anyone in the world to use. : https://about.jstor.org/whats-in-jstor/books/open-access-books-jstor/
e-books directory 10,173 Books : http://www.e-booksdirectory.com/
In Tech open Books : https://www.intechopen.com/books
Project Gutenberg : http://www.gutenberg.org/
The Complete Works of William Shakespeare : http://shakespeare.mit.edu/index.html
This is an open access textbook publishing initiative established by State University of New York libraries and supported by SUNY Innovative Instruction Technology Grants. : https://textbog/browse-by-auoks.opensuny.orthor/
Open Textbook Library hosted by the University of Minnesota. :
It covers over 160 college-level textbooks with an emphasis on Science and related fields.
Virtual textbook of organic chemistry provides fully operational organic chemistry textbook, divided into two overarching topics of General Principles and Functional Group Reactions. : https://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/intro1.htm
Boundless.com offers the textbooks and reading materials on chemistry. : https://www.boundless.com/blog/immigrant-chemists/
Saylor.org Bookshelf : https://www.saylor.org/books/
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Books Should Be Free (7,000) : http://www.loyalbooks.com/
Educational Technology Clearinghouse (about 200 audio books) : https://etc.usf.edu/lit2go/
Free Classic Audio books (100+audio books) : http://www.freeclassicaudiobooks.com/
Librivox (9,000+audiobooks) : https://librivox.org/
Naropa Poetics Audio Archives (817) : https://archive.org/details/naropa
Project Gutenberg – ebooks (2000+audio books) : https://www.learnoutloud.com/Free-Audiobooks
Librivox (9,000+audiobooks) : https://librivox.org
Naropa Poetics Audio Archives (817) : https://archive.org/details/naropa
Project Gutenberg – ebooks (2000+audio books) : http://alexwilson.com/telltale/spokenalexandria/
Storynory (Several hundreds of audio books) : https://www.storynory.com/
The Internet Archive (9,954) : https://archive.org/details/librivoxaudio
Thought Audio : http://thoughtaudio.com/
தமிழ் இணையக் கல்விக்கழகம் - TAMIL VIRTUAL ACADEMY : http://www.tamilvu.org/library/dicindex.htm
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Free Tamil Books, Tamil PDF ebooks and ePub Tamil collection for download online : http://books.tamilcube.com/tamil/
Rare Books
The "Rare Book Room" site has been constructed as an educational site intended to allow the visitor to examine and read some of the great books of the world.