Nothing wrong with studying a little Microeconomic theory. Why did he buy that? What was he thinking?
We used it in both of my graduate micro classes and it made me want to hunt Hal Varian down and personally thank him for not torturing me with his Micro book. If you're reading Mas-Colell for fun you need to commit yourself to St. Elizabeth's immediately. Seriously, everything about this book is torture - the material, the font, the book itself (it weights around 4lbs).
I'm going through my notes and it (Mas-Colell) again for a refresher before my interviews start. Good thing most of these jobs are straight econometrics, I don't think I could handle having to spend that much time obsessing over utility functions. Instead it'll be variance inflation factors, differential item functioning, collinearity, and logit models. Lucky me.