I added this course a week late in the summer (giving me only 4 1/2 weeks to learn the material), and still found it somewhat easy. I did put in my fair share of studying, but his exams were pretty easy. Except for one problem on the midterm that you had to work backwards through, the questions were somewhat trivial. Yoon was a good lecturer in that he took his time to make sure we understood topics. One downside of him taking his time was the fact that he lectured the full time, every time (with a very small break.) I do not think he grades on a curve either, but that isn't neccessary with his tests. One person below mentioned he had "Ravetch-like exams." I have not had Ravetch yet (taking him for 120B), but if his exams are like Yoon's, then I don't know what all the bitching is about. Maybe the reason for the easy final was due to the fact that it was a summer course, who knows. Bottom line: I highly recommend Professor Yoon. You will learn a lot, and get the grade you deserve!