The only cookery book my mother owns is one by Madhur Jaffrey, which gives some idea of how well respected she is. My mother learnt from her mother and grandmother, and what she doesn't know about classical Indian cooking from the Gujerat region isn't worth knowing!
I learnt from my mum but not being anywhere near as talented as her, and not being able to devote my whole life to cooking (though I so badly wish I could!), I own a few more books than her LOL!

The ones I rate most highly are, in no particular order:
- Madhur Jaffrey "Indian Cookery" (ISBN 0563164913). Authentic and delicious. As close to my family heirloom recipes as I've found anywhere.
- Charmaine Solomon "The Complete Asian Cookbook" (ISBN 9781904010180). Again, authentic, and with the added bonus of covering most Asian cuisines!
- Marut Sikka "Indian Flavours" (ISBN 0760780668). Tasty recipes, with a different angle - recipes are listed by their main flavouring, so you can explore different spices.
- Kris Dhillon "The Curry Secret" (ISBN 9780716021919). Starts with the absloute basics, so you build up a solid foundation from which to develop and explore.
Other excellent chefs, who put a modern twist on Indian cuisine are Atul Kochar (The only Indian restaurant to have a Michelin star), Cyrus Todiwala, Anjum Anand and Manju Malhi.
I don't own any of their books, but have done a masterclass with Atul (an afternoon in the presence of true genius - a humbling experience!), and eaten at his and Cyrus's restaurants, and their touch with flavouring is divine...
So, there you are! My personal views on what constitutes really good Indian food! Others may disagree, but as the saying goes - "It's my opinion and therefore a fact..." LOL!
One of these days, I will type up my mother's recipes and persuade her to let me publish them...