The Yawning Portal is the adaptation of several of the classic dungeons and dragons Campaigns/dungeons to the new D&D format. The Sunless Citadel, The Forge of Fury, The Hidden shrine of Tamoachan, White Plains mountain and several others. Each adventure gives the Dungeon master a synopsis of the adventure, what levels of character/ how many characters are needed and what they will need in order to survive. The book leads the DM and characters from first level to as high as 14-15. When you are done with this book you are an experienced D&D player. I highly recommend this book and think its a great addition to any Dungeons and dragons Library.