Some books can be viewed in your web client while other are available for download inPDFformat.
Most of these websites specialize in free textbooks.
There are also other websites that offerfree audiobooksandfree e-books.

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First Stop for Free Books: Google
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Search multiple websites at once.
Very effective at finding any free textbook.
Limited range of file types are supported.

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Google should be the first place you go to find free textbooks online.
Using a search engine like Google will scour the whole web for textbook PDFs.
However, instead of a general search, you’ll want to take advantage of Google’s filetype command.

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Google Scholaris anothersearch engine from Googlethat you should try along with a Google search.
It’s a great place to find all sorts of academic-oriented content.
Biggest Selection of Textbooks: Bookboon
Over 1,000 free textbooks.

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Website is extremely easy to use.
Several categories to browse through.
Access to more textbooks requires a paid membership.

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Bookboon should definitely be your second method of finding free textbooks online.
And several business e-books and the option to block ads are available with a business account.
There’s a 30-day trial if you want to see what that’s like.

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Best Mobile App for Free Textbooks: OpenStax
View online or download the textbook PDF.
Read free textbooks from the OpenStax mobile app.
This project was initially kicked off for college students by the Bill and Melinda Gates Foundation.

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Links to Free Textbooks: Open Culture
Hundreds of free textbook download links.
Most links go to PDF; no extra searching required.
Textbooks are categorized by subject.

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Reliability not a given; textbooks are on external sites.
Finding the exact book you need can be challenging.
Search Engine for Textbooks: MERLOT
Find free textbooks on multiple sites at once.

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Tons of filtering and sorting options to narrow results.
Sign up for alerts when new textbooks are added.
Textbooks stored on other sites.

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Links may end up as redirects or dead links.
you could search for free textbooks on MERLOT by title, ISBN, or author.
There are thousands of books to pick from, and they’re all completely free.

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Free Books for Free Classes: MIT OpenCourseWare
Includes a page with only online textbooks.
Supports advanced search commands.
Convenient “PDF only” filter.

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Includes PDF textbooks only for specific classes at MIT.
Free Textbook Finder: Open Textbook Library
Hundreds of free textbooks.
Textbooks cover common subjects.

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User account not required.
Very basic search tool.
All books are hosted on external sites.
Hundreds of peer-reviewed and free textbooks are available at Open Textbook Library.
There’s aPDFbutton you must click to reach the actual download page.
There’s also sometimes an option for reading the textbook online.
The Wikipedia of Textbooks: Wikibooks
Huge range of subjects.
Run by the same company as Wikipedia.
Some textbooks are PDFs.
Anyone can add annotations or edits.
Books can change because they’re open for editing.
Most textbooks must be read online.
This free textbook website is run by its visitors, much likeWikipedia.
This open-to-all philosophy means that some books are only partially finished.
Free Books for Every Grade Level: OER Commons
Super detailed descriptions of the textbooks.
you’re able to view all the books online.
Lots of helpful filtering options.
Might run into non-textbook materials like audio or video.
Each download page provides a link to view the textbook online in your surfing app.
Download textbooks in a few different file formats.
Several ways to browse the textbooks.
Some textbooks are scanned and aren’t as easy to read.
Free K-12 Textbooks: Curriki
Range of textbooks meant for K-12 students.
Must create a free account to download textbooks.
Some download links don’t work.
There are books for all grade levels including K-12 and college.
This resources also has textbooks for special education and professional development.
Free Public Domain Books: Project Gutenberg
Multiple download options.
you might read the textbook online if you want.
Limited selection of school textbooks.
Most of the books are very old.
Project Gutenberg offers a wide selection of over 70,000 texts.
Many are e-books in the public domain, but there are also free textbooks.
Free Books Message Boards: Reddit User Submissions
Updates frequently with new submissions.
Help from other students seeking free books.
Many older links no longer work.
Some links might violate copyrights.
It’s common for users to share links to free textbooks and websites where free books can be downloaded.
Not all of the links are valid because some older ones have been taken down.