Bobby A.
Yelp
If you're searching for a particular cookbook and haven't been able to find it anywhere else, chances are you'll find it here.
Beautifully lit, cookbooks here are organized by type and genre (i.e French, Italian, Indian, etc.), you're bound to find something here. The back part of the shop is where they hold cooking classes, often with known Montreal cooks and chefs. If you check out their website, you'll see that most of these workshops are already sold-out, so if you're like me and like taking a refresher course once in a  while, then keep an eye open and register early.
Jonathan Cheung is also very friendly and chances are if you can't find what you're looking, he'll be able to help you out and get it.
Mind you, it's not cheap. Most of the books are actually hardcover, not paperback so the quality is there.