There's a lot of advertising and spam for sites that promise to provide free books, but there are a couple reliable, long-lasting sites that provide extensive free collections.   Project Gutenberg hosts a large volunteer-provided collection of books without U.S. copyright protection, usually because the author died more than 70 years ago. All of them are free, almost all of them are available in plain text for any computer, and many are available in eBook reader formats as well.   Google Books has an extensive and varied collection, but not all of it is fully available or free. Books under copyright protection usually only have a few pages displayed, but sometimes there is a link provided for purchasing the full version. If you are studying an academic subject, or are interested in historical works, books in these fields may be easier to find online than in physical form. Take a look at the following free, specialized collections:  Use the HathiTrust website to search for books in many academic collections, including many free eBooks. Some materials, but not all, are restricted to members of universities or other academic institutions. A large collection of classical Greek and Roman literature is available through Tufts University's Perseus project. The Library of Congress has an online collection of rare historical documents and a few other old books that can be difficult to find anywhere else. Companies that sell eBook readers often have their own collection of eBooks, including free options. If you do not have an eBook reader device, you can download a free program to access the Kindle collection on your Windows or Mac computer, or use a non-proprietary database such as FeedBooks by installing Adobe Digital Editions for free. Apps are also available for most eBook databases in the app stores of all major phone and tablet manufacturers. If you are trying to track down a specific book, and it is not available in any of the above collections, an online search may locate it on another website. Keep in mind...

TL;DR in Indonesian:
Telusuri koleksi buku gratis. Temukan buku langka, bersejarah, atau akademis dari internet. Telusuri buku gratis pada basis data buku digital. Temukan buku tertentu dari internet.