Jacques Derrida
Jacques Derrida is the leader of the Deconstructionist movement. Borrowing from Nietzsche's process of genealogy, deconstruction seeks to read a text against itself. This is done through the revealing of the signs every sign is pointing to, in infinite reference. Deconstruction stipulates that a subject of interest (such as a text) can be better understood through this manner. Through a word Derrida is hesitant to use, deconstruction allows the reconstruction of new meanings or better understandings.
A critical component of Deconstruction is the concept of Differánce. Differánce relies on the space, the difference, between every sign. It is in this difference between signs that the meaning of signs is possible. One way to describe Differánce: The difference of difference is Differánce.
To put it more simply (a hard task with Derrida), it is only by the distinction of symbols from one another that gives rise to their individual capacity. However, these symbols can not stand on their own - they require other symbols and signs to give them their Differánce.