Creative Commons and textbooks

Anyone who has had to order textbooks for students knows how expensive they are. Here's something that I hope may end up a trend amongst academics: Creative Commons licensed texts. P.D. Magnus wrote a logic textbook, forall x, which he made available under the CC license; and now David Morris of the University of Lethbridge has used it as the basis on which to write an abstract mathematics textbook, Proofs and Concepts. With luck, this is a new dynamic of the new media, that will benefit education even if it takes away some revenue from academic publishers. For work that is fully created (rather than using existing material) it looks to be a good way to get material out there. If demand-publishing sites become more widely available, you can even get a hard copy version done nicely.