The Best Open Educational Resource Textbooks

OpenStax: OpenStax is a nonprofit organization that creates high-quality, peer-reviewed textbooks that are available for free online. They offer textbooks in a variety of subjects, including science, math, and social sciences. Project Gutenberg: Project Gutenberg is one of the oldest sources of free e-books on the internet, with over 60,000 titles available. They have a wide selection of textbooks in various subjects, including literature, history, and science. LibreTexts: LibreTexts is a nonprofit organization that creates open educational resources, including textbooks, for a variety of subjects. They also offer a wide range of multimedia resources and interactive tools to enhance the learning experience. Bookboon: Bookboon is an online publisher of free e-books for students and professionals. They have a wide selection of textbooks in various subjects, including business, engineering, and IT. Khan Academy: Khan Academy is a nonprofit organization that offers free online courses and resources, including textbooks, in a wide range of subjects. They also offer interactive exercises and quizzes to help learners test their understanding. Saylor Academy: Saylor Academy offers a wide range of free online courses and resources, including textbooks, in subjects such as business, history, and science. They also offer self-paced, online proctored exams to help learners earn college credit. Wikibooks: Wikibooks is a Wikimedia project that offers a wide range of open-licensed textbooks in a variety of subjects. The textbooks are written by volunteers and are constantly being updated.