[wp-hackers] I'm interested in a good book

[Rick Maltese]

I need an advanced book on Wordpress that explains the database
and hopefully has a lot of examples. I am not very good with PHP
and as I understand the wpdb class has numerous functions
that are unique to the class.
I need a good review of how to send data from a form to a new form
and capture it all in a database. I have been told that the gravity plugin
handles this very well. Anyone else here have dealings with the gravity
plugin?

Thanks Rick Maltese