I love "Mastering the Art of French Cooking". Can someone recommend similar books for other cuisines?
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