The State of Maryland College Textbook Competition and Affordability Act of 2009 codified some of the practices that faculty used (even before the Act was passed into law) to keep the cost of textbooks lower. Since then, the landscape for mathematics textbooks has changed. These changes are less noticeable for the upper-level undergraduate math courses (and barely noticeable for the graduate courses in mathematics), but they have been quite substantial for lower-level high-enrollment mathematics courses.

Most of the time, the students are buying not a textbook, but electronic access. And they are not exactly “buying”: the access fee is billed to the student account, unless the student takes action to opt out. Frequently, access is provided not directly by a publisher, but by an aggregator company that delivers electronic content. The prices are somewhat lower than for physical copies (something like $70 for one-semester access last time I checked), but, keeping in mind that the physical copy of the textbook can be re-sold, the overall cost did not decrease much.

I am happy to say that in mathematics, there is a robust movement towards open education resources. There are projects like OpenStax that assemble and host open-source textbooks. The books are available electronically; for students who prefer (or need) hard copies of the books, they can be ordered from Amazon for a nominal price. A softcover copy of College Algebra, for example, can be ordered for about $45. I taught Calculus 1 and 2 with OpenStax books. There are occasional errors in the text (I remember some in Calculus 2 book), but they can be reported to OpenStax. I was told that the errors are fixed twice a year (winter and summer breaks) in electronic version and once a year in the print version. Unlike commercial publishers, OpenStax does not “come with” a homework system, a system that can algorithmically generate slightly different versions of a problem and automatically grade the assignment, offering immediate feedback to the students. Luckily, there is an open-source homework system, called WeBWorK. I describe it more here.

As the OER movement in mathematics matures, it is now possible to systematically address:

**Quality of text**. Books published commercially typically undergo some review. How can an instructor know whether a freely available book is of good quality? People will look at the table of contents and spot-check some of the sections, but sometimes it is hard to tell how well the book will work until you start teaching with it. American Institute of Mathematics has a list of curated OER textbook in math. Each textbook on the list meets the evaluation criteria, in the judgement of the AIM editorial board.**Integration of online homework and interactive exercises**.**Difference between print and online versions and accessibility**. Many textbooks are designed to be primarily read online, but some students either prefer to have or need to have a print version. So if the online version is updated, the print version has to be updated as well. Accessible versions of the textbook (for example EPUB, Braille) must be updated as well. This creates substantial overhead for the authors, unless… Unless there is a system that allows to write a single source material for the book and then compile that source into all these formats. The Active Calculus textbook referenced above is authored with a system like that, called PreTeXt.

Online versions of textbooks lighten students’ backpacks and make the marginal cost of accessing material close to zero. They can also have an interactive component, allowing students to plot a graph of a function or to submit their answer to an in-text exercise. It is convenient when a homework problem has links to relevant concepts and examples in text. A lot of these capabilities are already there. For example, check out exercises in Active Calculus that can be activated and graded in-place.

American Institute of Mathematics has compiled a