From the Introduction:
Changeling: The Dreaming is a roleplaying game. It is a beautifully illustrated, full-color, hardcover book that explores the hidden world of the faerie folk trapped on Earth. It gives you rules for creating your own changeling character, and describes the setting and history of the fae. What happens next is up to you.
This booklet is a simplified version of Changeling: The Dreaming. It gives you the highlights of the Changeling setting and rules, the core information you need to play a game. Try it out. If you like it, the rulebook is available in most book, hobby and comic stores.