I like my curries.  I have a couple of recipe books and I have my staple recipes, but I don’t feel I really understand Indian spices – I think it is because I’m  used to cooking where I know what affect each of the ingredients has on the dish, whereas in Indian cooking there is often a large number of spices that goes in to one dish to give it a particular complex overall flavour.  What’s the affect of each different spice?  How do they work together?  What’s the impact on how and at what stage you cook each spice?

I’m on the lookout for a book that can help me to understand the Indian food, specifically how to use and blend spices.  Any recommendations?