This book presents a stage in the evolution of a theory of modality meanings and forms. It covers exclusively complements. There are two questions that this book addresses. Can one find a small, finite set of meanings which systematically underlies the enormous variety of meanings found in complements? And can one make any predictions from this set of meanings about the variety of forms they take? The answer to both questions is yes. The author convincingly shows how a multiplicity of sentence meanings and forms can be accounted for by breaking down sentence meaning into a small set of modules and howing how these modules combine to express certain meanings and how complement forms are related to them and their combinations.