From the publisher's website:
Swashbuckling Adventures brings daring highwaymen, fearsome pirates, and courageous duelists to the d20 System. Designed to work in any campaign, Swashbuckling Adventures features the award-winning setting of 7th Sea, the World of Theah. Everything needed for players and game masters to get started has been included. Features dozens of new character and prestige classes as well as new combat options, rules for dueling, a system for high seas battles, and more! Swashbuckling Adventures will be the definitive book for the swashbuckling genre in the d20 System.
From the back of the book:
From the open seas to the king's palace, a new brand of excitement awaits!
Two hundred years from the world of high fantasy, a different kind of world exists: where daring musketeers fight injustice in the name of the king, bold pirates claim riches with a blast of grapeshot, and matters of honor are settled at the end of a blade. It is the world of Errol Flynn and Alexandre Dumas, the world of Captiain Blood and the Count of Monte Cristo. It is the world of swashbuckling...and now, it is open to you.
Learn what it means to seek hidden treasure, to plot terrible revenge, to protect the innocent with nothing more than a quick tongue and a quicker sword. Sail with daring privateers in search of fabulous riches, plunder the wealthy as a charming highwayman, or thwart dastardly villains as one of the famous musketeers. From the halls of power where noble courtiers plot endless intrigue, to the wharfside docks where vicious sailors will kill you for your boots, it's all waiting between these covers.
Welcome to Swashbuckling Adventures!