[thebear]

After the initial excitement ;-) had settled down in the mid-nineties, it was, on order of magnitude, about $100 per year. Every once in a while, an interested mathematician would buy a copy. Other than that, in order to sell such a book, there has to be a graduate level class on the subject at some university (attended typically by about 5 people), and the teacher has to pick your book over a handful of other options.

I haven't kept track of the grand total that I made off the book, but it would certainly be a rather crappy used VW Golf.

I am so far removed from academia now that I have never thought about how I would publish a book like that today. My first impulse would be to make it a free ebook. Web search for "free course textbooks" indicates that this is not unheard of. Does anyone know how common it is, at various levels of higher education?

[spike021]

From what I've experienced, it's common to have mostly expensive texts (for undergrad level) that can reach upwards of $175. Occasionally there are free texts from professors at other universities, or just authors in general. But more often than not they're quite pricey.

Free would be great! I think a lot of students go the alternative route and torrent books or just Google to find their respective .pdf's without paying after they see the price tag at the campus store/amazon/ebay.