The recent rapid development of transformational grammars has incorpo rated some strong claims in the areas of semantics and co-occurrence. The earlier structuralists relied on a minimum of information about the meaning of strings of a language. They asked only if strings of sounds were different in meaning - or simply were different words or phrases. Current transfor mational grammars, on the other hand, set as their goal the production of exactly the meaningful strings of a language. Stated slightly differently, they wish to specify exactly which strings of a language can occur together (meaningfully) in a given order. The present book purports to show that transformational grammar is in dependent of the current trends in semantics. I claim that exciting and sophisticated transformational grammars are required for describing when strings of a language mean the same, that is, for describing when strings of a language are paraphrases of each other. This task can be quite naturally limited to a project of much weaker semantic claims than those which are current in transformational linguistics.