check this new initiative from HRD and IIT Kharagpur.6.5 million books are now available in one single portal, where you can read online, or download the books. There are text books, audio and video content. Just browsing them all may take years! Enjoy. National Digital Library is an initiative by HRD ministry. It is a huge collection of learning resources (68 lakh books) from primary to PG level. Students can use it free of charge.
To register, go to: https://ndl.iitkgp.ac.in