For an introduction to Indian cuisine, Madhur Jaffrey's Indian Cooking can't be beat. The recipes are all easy to follow and to prepare, with ingredients, in both American and metric measurement system, listed in a column next to the recipes. Jaffrey does not concentrate on Indian vegetarian dishes, although many of the recipes ARE vegetarian. There are even a few beef recipes reflecting the non-Hindu population. (The beef baked in yogurt and black pepper is delicious!)
Jaffrey includes a descriptive guide to Indian spices and ingredients as well as a chapter on cooking techniques. The section on breads is fantastic. I never thought I could make poori at home, and yet they turned out perfectly. I make naan fairly frequently, using a breadmaker to knead the dough, because it's my family's favorite. Other excellent dishes include Dry Potatoes with Ginger and Garlic, Gujerati-style Green Beans, and Spicy Baked Chicken. (The recipes are titled in English, with the Indian names in parentheses underneath.)
Anyone with a basic know-how of cooking should be able to succeed with these recipes.