What book is the best PHP reference to own?

Question

(paper only)

Answer 1

Seriously, any paper only reference is ok, but nothing compared to simply printing out the online manual. Luckily, the PHP guys expect people to print it. They have multiple downloadable formats at http://us.php.net/download-docs.php

Answer 2

Of the 5-6 books I own, I use my Core PHP Programming, third edition, by Leon Atkinson and Zeev Suraski the most. This is for PHP 5, of course.

If you're a complete beginner to PHP you might want to go with something with more examples / walk-throughs, though. My Visual Quickpro Guide, PHP 5 Advanced, isn't bad for that. By Larry Ullman

Answer 3

for learning:
(1) Programming PHP (Rasmus Lerdorf & Kevin Tatroe)
(2) Learning PHP 5 (David Sklar)

for reference:
PHP in a Nutshell (Paul Hudson)
PHP Pocket Reference (Rasmus Lerdorf)

...you may notice I'm an O'Reilly bigot, but I think their books are the tops