Natarajan was a GREAT professor!!! He explained everything very clearly and also posted lecture notes online so that you don't even have to read the book. He also gives out homework problem solutions and practice tests with solutions. He really tries to prepare you for his tests. His tests were very fair and straightforward. He really tries to test you on what you learned in the class, instead of trying to trick you. If you attend lecture, read the lecture notes, and do the homework problems, you'll do well on his tests, unlike Ravetch where you study like crazy and still get a bad grade. I really recommend him for 120A!