I have several books dedicated to the art of curry.
Beyond a doubt the best book around is ...
<!-- m --><a class="postlink" href="http://www.amazon.co.uk/Indian-Housewifes-Recipe-Book-Right/dp/0716020785" onclick="window.open(this.href);return false;">http://www.amazon.co.uk/Indian-Housewif ... 0716020785</a><!-- m -->
Being paperback and well used is an issue - I've been using these formulae for around 15 years, and am on my sixth copy of this book - two have eventually fallen beyond repair and others I've given away to impressed punters. If you like curry then this book is a must :twisted:
(NB. in a never ending search of perfection I have just ordered a copy of neo's recommendation)