From the introduction:
Many fantasy RPGs assume a medieval technological period. The bow is the supreme ranged weapon. If magic is present, sorcery can also fill a role similar to siege weaponry and deliver devastating attacks. However, some players and GMs want something a little more modern.
Modern, of course, being a relative term.
Some players want flintlocks for a high-seas pirate game. Others want musketeers and other similar swashbucklers to make an appearance. Even others want to have elves and dwarves in an Old West-style setting or maybe even have airships duke it out with black powder cannons.
Whatever the case may be, there are several questions every GM and player must ask and consider before adding firearms to a fantasy game. That’s the aim of this book. There is no one “correct” way to introduce a new mechanics. This book offers different types of firearms, different rules options, as well as new feats, items, and options should you decide to include firearms in your campaign.