Dr. Grossman is rather difficult but it is matched by his willingness to help. I took two courses with him and throughout both quarters he would stay well after office hours to help me (sometimes 3 hours over and this was not an isolated event). The homework questions that he writes are difficult and I almost always had to ask him how to do it but they make you think and you get a good grasp of the material after that. So, he is difficult but take the initiative to ask for help and you will be okay. Good luck.