The following section attempts to identify the best OER mathematics textbooks in each subject area. The selected texts are meant to serve as examples of what users of high quality OER should expect and what producers of future OER should strive to achieve. Of course, there are numerous reasons for adopting a specific textbook; no one individual’s professional opinion will satisfy all points of view on this subject. However, this essay uses insights gleaned from a wealth of experience using OER in the classroom to champion a few textbooks that should be easy to adopt.
Instructors are advised to consider all quality texts before making a final selection. Though cost and openness are important criteria to consider, there are of course many other factors; the selected texts may not satisfy them all. As a reminder, only topics from the standard undergraduate curriculum in mathematics will be considered below. In particular, topics from graduate level mathematics and development mathematics will be omitted from this discussion, though there exists a rich collection of OER in both those arenas. Finally, while the OpenStax textbooks mentioned above do exemplify a high standard of OER textbooks, the selected textbooks below were deliberately chosen from outside the OpenStax catalog; that said, potential adopters are encouraged to seriously consider the OpenStax catalog if a course falls under their curriculum.