Just been on holiday for a couple of weeks and took the cookbook
India by Pushpesh Pant
Not BIR but the recipes come from all regions of India and well worth a read
The book boasts of 1000 recipes
It covers spice mixes and pastes pickles chutneys Raitas snacks , appetizers ,mains ,pulses,breads, rice
In my opinion well worth a place on the side board with the other 20 odd curry books ;D