The concept of the Love Languages is, to me, one of the most important and practical theories I have learned in my pursuit of relational bliss.
According to Dr. Gary Chapman, author of the successful book "The Five Love Languages", the
five love languages include:
1) Affirmation - verbal compliments, encouragement, confidence boost, etc.
2) Quality time.
3) Receiving gifts.
4) Acts of service - helping with housework, simple chores, etc.
5) Physical touch - not just sexual intercourse, but sometimes as simple as a kiss, a hug, or a hand on the shoulder.
As the theory goes, each of us speak, and is most receptive of, one or more of the five emotional languages above.
The problem is, our love language may or may not be the same as our spouse / friend / children. A lot of the relationship conflicts (not just marriage, but friendship or parent-children conflicts) arise because of a misinterpretation of the other's love language. For example, I may express my love to you by spending hours in the kitchen cooking a fancy meal (act of service), when all you want is for me to sit beside you and chat about your day (quality time). Nobody is at fault, it's just a mismatch and misunderstanding of each other's love language. Once we have a better understanding of our spouse's love language, then we can express our love in a way which is most effective, hence reducing misunderstanding and frustrations.
This book is good for anyone who is in any form of relationship.