I had to learn PHP when I began customizing an installation of the BioArray Software Environment (BASE). BASE is a large system written mostly in PHP. PHP has a syntax that is fairly similar to Perl (although how PHP is used is very different from Perl), so I’ve been attempting to learn PHP without having to buy seven or eight books. These are the books I have used.

Publisher’s information Comments
PHP Cookbook
by David Sklar & Adam Trachtenberg
November 2002
ISBN 1-56592-681-1

Web Database Applications with PHP and MySQL, 2nd Edition
by Hugh E. Williams & David Lane
May 2004
ISBN 1-566-00543-1