The Depth relationship is like two deep seas connected by an underground aquifer. On the surface it may appear still, with little visible movement, but beneath it stretches a rich and complex world. Both individuals possess strong inward energy and engage in dialogue at deep layers of thought, emotion, and imagery. Dialogue in this relationship differs qualitatively from ordinary conversation. Meaning behind words, understanding within silence, the sharing of unexpressed emotions -- these are the essence of the Depth relationship. In neuroscience terms, the default mode network (the brain region involved in introspection and self-referential thought) may synchronize when the two are together. This is a rare and precious phenomenon.