Indian food is one of my favorite cuisines. Although I think that the term 'Indian' food is very misleading. India is a huge country with many different regional cuisines and access to certain spices and vegetables, and has a rich culinary tradition. If you are as interested in food as I am, particularly the cultural influences that food has on society and vice versa, then I suggest Curry: A Tale of Cooks and Conquerors, by Lizzie Colllingham. In this book the author examines Indian cuisine and how it has both influenced and been influenced by different culinary traditions brought by conquerors and outside influences. It even contains a few recipes that relate to each chapter. This book is a great example of how to examine change in foodways and how culture and foods influence one another.
For more readings on Indian cuisine and culinary traditions see
1981 Gastro-Politics in Hindu South Asia. American Ethnologist 8(3): 494-511.
1988 How to Make a National Cuisine: Cookbooks in Contemporary India. Comparative Studies in Society and History 30(1): 3-24.