Jeff Moser writes How .NET Regular Expressions Really Work.
I've got a soft spot for regular expressions (programming Perl can do that to you), and while I understand backtracking and greedy / lazy matching, I've never actually read the source code for a regex library before.
If you haven't either, and want to benefit from someone else's description of the 14,000 lines of .NET regular expression library, you'll enjoy this post.
Kirk
Disclaimer The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way.