HaloPlayer - 11:23 am on Sep 30, 2012 (gmt 0)

Something like this will work for me do you think?:

RewriteEngine on
RewriteRule ^book/([a-z]+/([a-z]+)$ book.php?$1=$2 [L]

Also do you think it is better to leave it without an extension or will adding a .htm or html for each URL be better for search engines?