This Review is concerned with the search of molecules to find a suitable partner with whom to form a bond. Whether an initial encounter results in a fixed bond depends on many critical issues, such as reciprocal compatibility in terms of size and shape, complementary reactivity, proper alignment of reactive groups, and medium effects. The chemist acts as the master of ceremony and finds a high reward in the case of a successful marriage. Giotto's painting "The wedding of Mary and Joseph" illustrates the principles of supramolecular chemistry involved.