In his early plastic age, the child presents an asymmetrical growth in what concerns his motor system, when compared with his cognitive system. The latter seems to be far ahead of the former. It consists of many sub-systems; the most outstanding of which being language. TRANSFORMATIONAL GRAMMAR has been striving for more than half a century to try and deal with this phenomenon. It has evolved from a model of rules to a model of principles, to end up with the Minimalist Program. This book presents the successive approximations that Transformational Grammar has gone through since its early insemination in1957 up to the Minimalist Program. After which, there is a critical chapter called "Occam's Razor". Finally, there is a chapter on "Logical Form" and an appendix that deals with the major transformations of early transformational grammar.