This is not an introduction to .htaccess… This is the evolution of the best of the best.
You've come to the right place if you are looking to acquire mad skills for using .htaccess files.
Originally (2003) this guide was known in certain hacker circles and hidden corners of the net as an ultimate .htaccess due to the powerful htaccess tricks and tips to bypass security on a webhost, and also because many of the tricks and examples were pretty impressive back then in that group.
This covers almost all settings of the .htaccess file and has examples.