Steven Forrest, Jodie Forrest. Skymates II: The Composite Chart. New York, Seven Paws Press, 2013.

Learn the art of reading composite charts - the hidden "third wheel" in every relationship. A person whose life drifts away from the blueprint of his or her birthchart grows dull, flat and depressed. It is the same for a couple - if their life together departs from the spirit of their composite chart, their relationship runs out of gas. They stop talking. Sex evaporates. They would rather watch TV than look into each others' eyes. In this book the Forrests provide the tools you need to explore this powerful astrological technique - theory, real-life practical examples, and an extensive cookbook section where you can jump-start your interpretations by looking up the precise meaning of any configuration.