Jacques Derrida was one of the most well known twentieth century philosophers. He was also one of the most prolific. Distancing himself from the various philosophical movements and traditions that preceded him on the French intellectual scene (phenomenology, existentialism, and structuralism), he developed a strategy called "deconstruction" in the mid 1960s. Although not purely negative, deconstruction is primarily concerned with something tantamount to a critique of the Western philosophical tradition. Deconstruction is generally presented via an analysis of specific texts. It seeks to expose, and then to subvert, the various binary oppositions that undergird our dominant ways of thinking—presence/absence, speech/writing, and so forth.
(Source: http://www.iep.utm.edu/derrida/)