OpenStax provides free, peer-reviewed, openly licensed textbooks and accompanying ancillary materials, such as slides and test banks. OpenStax textbooks have been adopted at numerous universities throughout the world. In the 2017 - 2018 academic year, use of OpenStax textbooks saved $145 million for students at over 4,000 schools.
Dr. Ted Sundstrom received the Daniel Solow Author's Award from the Mathematical Association of America in recognition of Mathematical Reasoning: Writing and Proof, an OER. The award celebrates authors of materials that have a positive impact on undergraduate mathematics education.
Active Calculus was written by Dr. Matt Boelkins, Professor in Grand Valley State University’s Department of Mathematics, and has been revised and improved upon over time by a community of educators. Dr. Boelkins explains why he chose to write and share the textbook on his website.