Absolutely essential for CMIS 412, but I don't think that's part of the major requirements anymore. Otherwise you don't need to have a firm grasp for anything other than your own personal enrichment.
Anyways, if you want to learn what the class teaches, try picking up Beebop to the Boolean Boogie, which does a much better and more thorough job of covering the same stuff. I think it was actually listed as one of the "additional reading" things in one of the textbook sections, and I have found it enormously helpful.