Tyler Durden is a fictional character from the book Fight Club, not to mention the movie of the same name that popularized Durden.

But to say Durden is just ‘a character’ is somewhat of an understatement; in fact the name Tyler Durden describes two distinct characters in the story, both that of the long-unnamed protagonist (played by Edward Norton) and his live-on-the-edge counterpart (played by Brad Pitt) who serves as an alternate personality of sorts.

The story begins with Durden’s life. He’s a man completely disenchanted with his life; he loathes that his identity is formed by the things he owns and hates his job (that of an automobile risk analysis official). His various neuroses conspire to keep him from getting any sleep, and Durden quickly becomes an insomniac.

He discovers, however, that there is one way of getting to sleep – joining self-help groups. After attending a testicular cancer group and discovering that he can sleep “like a baby” after having a good cry, Durden becomes reliant on the groups, and attends them at night multiple times a week. That he isn’t plagued by any of the problems associated with each group doesn’t bother him.

But a girl soon begins to join his groups, a girl named Marla – and like Durden, she’s faking her maladies to enjoy to compassion others offer her. Durden finds himself unable to cry (and sleep) while she’s present, knowing there’s another faker, and they’re forced to split up their days in an effort to stay away from each other.

It’s around this time that Durden’s neuroses kick into overdrive and a new man enters his life: Tyler Durden. A figment of Durden’s imagination (to this point Durden had not once been named), this new Tyler is everything Durden seems to want to be: proactive, unwilling to put up with society’s crap and totally anarchistic. Together they discover a new outlet for Durden’s pain, and establish a society wherein men can fight it out, night after night, to let loose their more primal sides. Fight Club is born.

But Tyler, who proves very active when Durden is asleep, quickly expands the business of Fight Club into a new organization: Project Mayhem. The goal of Project Mayhem, Durden eventually learns, is to destroy a building using explosives (which building it is depends on whether one is reading the book or watching the movie). In the book Tyler is unsuccessful in his plans, and the building isn’t destroyed; the secondary persona of Tyler then vanishes. In the movie he is very successful, and Durden and Marla watch as a handful of large banks tumble down in the night. The persona only disappears in the film when Durden shoots himself (though the shot doesn’t kill him).

It is important to note that Tyler Durden is not the protagonist’s real name, but that of the split personality. However Marla calls the protagonist by the name ‘ Tyler ’, so calling him ‘Tyler Durden’ isn’t wholly without merit.