Derick Rethans has contributed in a number of ways to the PHP project, including the Xdebug debugging tool, the mcrypt, date and input-filter extensions, bug fixes, additions and leading the QA team. He's a frequent lecturer at conferences, the author of php|architect's Guide to Date and Time Programming, and the co-author of PHP 5 Power Programming. Derick works as an independent contractor doing various PHP related jobs while focussing on internals and extensions. In his spare time he likes to travel, hike, ski and practise photography.