This paper investigates into the background of the spectacular success of the French philosopher Jacques Derrida (1930-2004), which seems to remain strong considering the fact that, as late as 2007, Derrida was still among the most quoted authors in the world, in humanities. The start of his career was the publication in 1967 of the extremely influential book On Grammatology devoted to the presentation of his chief idea known as deconstructionism. To put it shortly, this term alludes to the practice of reading and interpreting texts – whether literary or philosophical – against the intentions of their authors, so as to make them say what they were probably never meant to say. This method or doctrine soon became extremely popular, especially indepartments of comparative literature or literary criticism, both in the U.S.A., in France and the rest of Europe. Along with it came an attitude of radical scepticism which came in handy in cases of opposition.What I try to do here is a close reading of De la grammatologie, in order to highlight flaws in Derrida's own text and argumentation. The conclusion reached is entirely in keeping with the spontaneous impression one gets from reading Derrida'stext. Apart from its tiring verbosity, his style is most of the time unbelievably obscure and even void of sense. Another recurrent problem is lack of referential exactness.But when, at times, the text becomes a bit less vague, it turns depreciatory and disdainful, as if to compensate for a lack of argumentative strength by hitting below the belt. Given these circumstances, the question is whether this text was originally meant to convey a serious theoretical discussion at all. An alternative interpretation discussed here consists in viewing it as a hoax played upon the reader to confuse him, the way the traditional "canular" was used in the famous École Normale Supérieure where Derrida was trained as a philosopher. (There exists a more compact version of this article in French on the following site: http://hdl.handle.net/2077/30607pp. 333-345)