• The Miracle of Mindfulness by Thich Nhat Hanh. I first read this book when I was in my mid-teens, I still find it one of the most accessible books on the theory and practice of mindfulness available today.
• On Killing: The Psychological Cost of Learning to Kill in War and Society by Dave Grossman. I went back to school with the intent of working in the field of combat-related PTSD. I read this book as an undergraduate and found it well-researched.
• FLOW: The Psychology of Optimal Experience by Mihaly Csikszentmihalyi. Another book I read as an undergraduate, Flow-states are a fascinating subject and explainable in a host of different metaphors and theraputic models.
• Arousal: The Secret Logic of Sexual Fantasies by Michael J. Bader. I first read this book when researching my dissertation. I was looking for a text to argue with and instead found one of the most "sexual minority positive" texts available on the subject of sexual fantasy, identity, and practice.
• The Seven Principles for Making Marriage Work: A Practical Guide from the Country's Foremost Relationship Expert by John M. Gottman and Nan Silver. I have a Level One Certification in the Gottman Technique, this book is one of the major reasons why I chose to pursue that training after learning about it in my graduate training.
• Passionate Marriage: Keeping Love & Intimacy Alive in Committed Relationships by David Schnarch. I found the focus on something other than just physical sensation and acts (the "sensate focus" model of sex therapy) as the road to sexual and emotional intimacy to be refreshing and illuminating when I first read this.  

The meaning of things lies not in the things themselves, but in our attitude towards them.
Antoine de Saint Exupery