Roberts seeks to show how and why world citizenship and mundialism--the building of global institutions--are essential for the human race to solve the growing problems of the environment, international violence, and other major world challenges. World citizenship is described from its origins, and its importance to solving current problems is made clear. Its necessary connection to federalism and democracy is stressed, while the inevitable consequent requirement of mundialism is discussed and emphasized. Mundialism describes the creation of structures needed by the emerging world community; it means, as Roberts points out, working for a new political organization of humankind involving the transfer of certain parts of national sovereignty to a World Federal Authority. This is an important synthetic and original work that will be of concern to those interested in world citizenship and peace issues.