Recommend a good Book to optimize my queries

Hi, would you be so nice as to recommend a good book to read to optimize my SQL to make my queries as fast as they can be, and also to optimize my use of indexes?

I'm working suddenly with too big a DB so all my past experience is getting in my way instead of helping me out. Thanks.

There are not much books about Firebird generally, and none (afaik) with deep informations about optimizing. "The Firebird Book" by Helen Borrie is good, but the informations about optimizing are too general to be easily applicable to big databases. The deep description of optimizing techinques would require whole book (generally, not only with Firebird). You either have to study/understand how Firebird works internally, or you can ask somebody to help with it (and even if it would not be for free, it would save you lot of time (and time is money ))

Ok, thanks...