Why Do I Feel Like an Imposter is an excellent handbook on Imposter Syndrome (although the author argues that it's not a syndrome at all; rather, it's a natural part of human behavior). I frequently struggle with IS and in the past, I used to let it get the better of me, but with therapy (and LOTS of constant reminders to myself) I've more or less overcome it. The thing I like about this book is that it doesn't lump everyone into a single category. It breaks down IS according to population: men at work, women at work, parents, teens, students, etc. Each chapter focuses on a particular group and discusses the "symptoms" of their version of imposter syndrome, gives theories about how it came to be, and suggests exercises for convincing yourself that you're not an imposter. If you're not sure what kind of imposter syndrome you have, or if you think you have multiple kinds, Why Do I Feel Like an Imposter can help you. The book can also help you support others by pointing them in the right direction.

The only drawback to this book is that if you've already done a basic search on Imposter Syndrome, the information in the book may not be new. Still, I recommend it because the organization allows you to easily flip to the right section depending on who you're mentoring.