From the back of the book:
Welcome to the first compilation from EN5ider Magazine for the 5th Edition of the world's oldest fantasy roleplaying game! Within these pages, you will find the details of seven new character classes for your games, designed to enhance the flavor and composition of your adventuring party.
Whether you are drawing cards to produce wondrous effects, delving into diabolical and forbidden secrets, embracing nature and chaos, or concocting fantastic new alchemical substances, you'll find a whole range of exciting and mysterious new character types within.
The material herein originally appeared in EN5ider Magazine, and is presented here revised and expanded.