My first university physics class had a "textbook" that was essentially the bound (as in textbook binding, not a comb binding) lecture notes of one of the department's professors. It was utterly hopeless if you didn't have that actual professor, but was great if you did. I didn't have him in lecture, but I did have him in the lab lecture part, so I got a great view of the difference. Crummy view of the physics, of course, but that's why courses can be repeated.
They had a different book the next semester, though. It was a genuine textbook, which was great (I passed the stupid class that semester), but it cost even more than the old, useless one.
