Mastering the Art of French Cooking does a fantastic job of teaching what you need to do to cook all of the classic French recipes and why you need to do it the way that is recommended.  Can anyone recommend similar books for Northern and Southern Italian, Spanish, Mexican, Japanese, Chinese (Cantonese, Szechuan ...) ... etc? 
French Cuisine (other than JC):  Patricia Wells - Bistro Cooking, At Home in Provence  Paula Wolfert - The Cooking of Southwest France (if you love ducks, that's the book for you)  Elizabeth David - French Provincial Cooking   I've also heard great things about Dorie Greenspan's recent Around My French Table, although reviewers note that as a contemporary French cooking has a lot of influences from around the globe (Asia, North Africa and even USA). However, if you'd like to find out what French people are likely too cook at home these days, this has to be a great resource.  Spanish Cuisine  Penelopa Casas - The Foods and Wines of Spain, Tapas  Portuguese  Jean Anderson - The Food of Portugal  Italian  Marcella Hazan - The Essentials of Classic Italian Cooking  Mexican  Rick Bayless - Authentic Mexican, Mexico One Plate At a Time  Russian  Anya von Bremzen - Please to the Table: The Russian Cookbook  German  Mimi Sheraton - The German Cookbook: A Complete Guide to Mastering Authentic German Cooking  Japanese  Shizuo Tsuji - Japanese Cooking: A Simple Art  Chinese  Irene Kuo - The Key To Chinese Cooking  Barbara Tropp - The Modern Art of Chinese Cooking  Thai  David Thompson - Thai Food  Indian  Julie Sani - Classic Indian Cooking, Classic Indian Vegetarian and Grains Cooking  Madhur Jaffrey - Indian Cooking, An Invitation to Indian Cooking, A Taste of India  Middle-Eastern  Claudia Roden - The New Book of Middle Eastern Food  Greek  Susanna Hoffman - The Olive and the Caper: Adventures in Greek Cooking  Diane Kochilas - The Food and Wine of Greece  South American  Filipe Rojas-Lombardi - The Art of South-American Cooking  Copeland Marks - False Tongues and Sunday Bread  Elisabeth L. Ortiz - A Taste of Latin America 