From the publisher:
You do not aim with your hand.
The Secrets of the Gunslinger offers 4 new archetypes, 30 new feats and one new monster template so that the vision you have of your gunslinger can easily be obtained an explored. It offers the Buccaneer of the Black Powder, so you can embrace the golden age of piracy; The Fire Artist which embraces the eastern traditon of marital arts and firearms; The Hexslinger bringing you a bit of flavor from the wierd west, and the Wandslinger for those campagin settings that don't have or allow firearms. The Gunslinger Wraith is a new monster template that focuses on an accursed firearm that continues to bring a soul back from beyond the grave, with a with ammunition that saps the lifeforce from its targets at range.