PHP had its roots 10 years ago, and it seems that students are already studying its origins, and the reasons behind why it was written, as a part of computer history.  Makes me feel very old! Here are some useful links.

Rasmus Lerdorf / Zend hall of Fame / history of PHP
Brief history and how that lead to PHP4's structure
Black Bean's history of PHP
Hitchhiker's Guide to PHP / Do you PHP - article by Rasmus Lerdorf
A further history
Brief history to 1998

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