Wikibooks: The Future of Textbooks?

I’m taking an advanced controls class this semester, and a classmate sent me this wikibooks link. I was unaware of this, but it seems like it has the potential to do away with textbooks completely, as you can even download the file as a .pdf.

Does this seem like a viable way to lower textbook costs while ensuring all students have access to the material?

<idealism-crushing ogre>
If a professor were to assign a wikibook as the class textbook, it would result in lower sales of a dead-tree book which was authored by/credited an esteemed colleague. This esteemed colleague would then choose not to assign the professor’s book in his own class, thereby bringing the whole system crashing down and Ending Civilization as Professors Know It.

Also, it would cut into profits for the university book stores, because they would be unable to buy back the textbooks for a pittance from starving students, then resell them at extortionate rates.
</ogre>

Ahem. Now that that’s out of my system…I think it’s a very cool concept, and there’s a lot of great stuff there. It’s subject to the same the quality-control problems that plague public wiki projects, but I still like it. It doesn’t have to be official or perfect to be useful. I don’t see it actually replacing textbooks any time soon, however.

Also, I hope your controls professor is better than mine were. Mine were known to actively lie to us about course material, as well as omit critical information.