Relationship

Eight Lessons for a Happier Marriage by Dr. William Glasser and Carleen Glasser

The Five Love Languages by Gary Chapman

Understanding Moods / Emotions

Daring Greatly by Brene Brown

The Dance of Anger by Harriett Lerner

Mind Over Mood Workbook by Dennis Greenberger and Christine Padesky (Excellent for Panic and Anxiety)

Your Depression Map by Randy Paterson

Parenting

Smart Discipline by Larry Koenig

How to talk so kids will listen and listen so kids will talk by Adele Faber

Smart Love: The Compassionate Alternative to Discipline by Martha Heineman Pieper and William Pieper

General 

Take Charge of Your Life: How to Get What you Need with Choice Theory Psychology by Dr. William Glasser

Too Soon Old, Too Late Smart: Thirty Things You Need to Know by Gordon Livingston

Health

8 Weeks to Optimum Health by Dr. Andrew Weil, and other various works. 

The Mayo Clinic Diet: Eat Well. Enjoy Life. Lose Weight. by the Mayo Clinic