One of the central themes of 'The Power of Two' is the importance of effective communication in a marriage. Heitler emphasizes that open and honest dialogue is crucial for resolving conflicts and understanding each other's needs. The book provides practical tips on how to communicate more effectively, including active listening and expressing feelings without blame.

Another key idea in the book is the significance of conflict resolution skills. Heitler explains that disagreements are a natural part of any relationship, but how couples handle these conflicts can make or break their marriage. The book offers strategies for resolving disputes in a constructive manner, helping couples to find common ground and strengthen their bond.

The Power of Two also highlights the importance of building emotional intimacy in a marriage. Heitler discusses how couples can deepen their connection by sharing their thoughts, feelings, and experiences with each other. The book provides exercises and activities that couples can do together to foster a sense of closeness and mutual understanding, ultimately leading to a more fulfilling and loving relationship.