From the introduction:
Jarlaxle’s Bag of Everything offers a host of new options for Dungeons & Dragons, and our journey through those options is accompanied by the notes of the rogue himself, Jarlaxle.
The dandy Jarlaxle, whose words easily work past his ill reputation, has gathered a deep understanding of others during his, let’s say, illustrious career as a mercenary leader. He was one of a small number of male udadrow who actually had significant power in a Lolth-worshiping city, although he increasingly spent little time in the city itself as he adventured abroad in the Underdark and the Lands Above. Charismatic and cunning, he opens his bag of tricks to others intrigued and like-minded as him.
Written for players and Dungeon Masters alike, this book offers options to enhance characters and campaigns in any D&D world, whether you're adventuring in Forgotten Realms, another official D&D setting, or a world of your own creation.