Several of my professors did the same. Some went as far as saying the particular text book was not necessary, suggesting we can choose our own or recommending a

Several of my professors did the same. Some went as far as saying the particular text book was not necessary, suggesting we can choose our own or recommending another. The important thing was the content of the course, with the source only being relevant for things like accuracy (which was rarely an issue for my field of study, at least for introductory texts which is what publishers tend to game). Just after I finished my studies things started becoming more difficult though, when additional instructional materials (graded tutorials, quizzes, and such) started going online.