Pushpesh Pant has taken a very scholarly approach to write probably the most definitive book on Indian cuisine. Arguably the only Indian cookbook you would ever need. Except for mine, of course.
This is a massive book and can be used as a reference for just about every Indian recipe I have ever seen. It makes, for me, a useful cross-reference to my grandmother’s books to clear up and understand inconsistencies.
You can read about this book on Goodreads.