Chief maintainer of the Perl 6 test suite who also writes a lot about Perl 6. He has several sites across the net, noteworthy here are his blogposts on http://perlgeek.de/blog-en/perl-6/ and his german site http://perl-6.de/, which is full of small Tutorials. He wrote also the software which runs http://perl6.org. And he is a co-author of the Open source Perl 6 book.