From publisher blurb:
The Crossbow is a powerful ranged weapon, designed to be easier to use and master than the traditional bow. In addition, the locking mechanism and the use of heavier bolts rather than lightweight arrows allows for a lot more potential to be packed into each shot. The trade-off, however, is that Crossbows are much slower early on, and take time, strength, and feats to match the sheer speed of traditional archers.
The Sidebar product line brings you an assortment of ideas, homebrew rules, and various options from the talented pool of writers at Fat Goblin Games for use with the Pathfinder Roleplaying Game.