This is by far one of the best 3rd party resources for 4th edition. This resource introduces a small extension to the 4th edition rules that lets players choose flaws for their character in exchange for receiving an extra feat. Both the flaws and merits listed in this book are very flavorful and explore a lot of new ground not covered in the WotC's resources. These options can really help you develop your character in new ways and make him/her feel unique. Want to play an aged Wizard, a hero that is dreadfully afraid of spiders, or a proficient teacher that can bolster your parties skills? There is mechanical support for all these things in this book and more. Everything looks really well balanced, though a few have a few "loopholes" that may require DM arbitration.