A chap called Dixon Crews has posted to reddit’s maths section asking for help with a writing project.

He’s writing an open source calculus text, based at OpenCalculus.org, which is aimed at students in their first semester of study. All the LaTeX source code is available in a repository at GitHub, so anyone with a working knowledge of version control can clone it and start adding material. He’s only a few pages in so far, so there’s plenty to do. It looks like a hobby project more than something serious.

This is by no means the first open source calculus textbook, or even the first one called *Open Calculus*. Matt Boelkins has been quietly plugging away at his *Open Calculus* for about a year. Matt’s doing things in a more rigorous manner – his textbook is currently available on request, and will only be more easily available once it’s been tested. Benjamin Crowell’s *Calculus* is also on GitHub and looks a lot more like a commercial textbook than other open textbooks, which tend not to elaborate on the default LaTeX style. Finally, there’s the *Oppikirjamaraton*, which produced a Finnish high school maths textbook in a weekend.

There’s actually a lot of work being done to create and collate open course material for maths. The American Institute of Mathematics has an Open Textbook Initiative which maintains a list of approved texts, and Rob Beezer keeps his own list of material at the site for his (reputedly very good) First Course in Linear Algebra.

There’s also, of course, the Wikibooks project’s maths section, and Project Gutenberg’s fantastic collection of lovingly reset out-of-copyright maths textbooks, mentioned here way back in April.

*Via MathUpdate on Twitter.*

Thank you. I think I’ll share the Crowell with my Calc I on their last day of class tomorrow. It’s very readable, and his approach, both the infinitesimal, with discrete examples, and the historical connections, is very different from what they’ve seen so far.

I think it would make a great way for them to understand calculus better.

I am, perhaps foolishly, also thinking about writing a(n open source) calculus textbook. I have two reasons: none of the textbooks are in the order I want, and none gave enough historical connection. If done as an ebook, it could also include links to many fabulous ideas in the blogs I follow.

Crowell may do enough of what I wanted (better than I could have, perhaps) that I can forget this thought, and go back to writing poetry in my spare time. ;^)

I also like the Hoffman text, which isn’t mentioned at the AIM site. Here’s my annotated list.