Cobb is a master in the art of extraction, which consists of stealing his mark's ideas by infiltrating their dreams and stealing valuable information from them. He is well known in the black market because of his level of expertise in the field of extraction. Cobb was implicated by his wife Mal in her death in a letter she filed with their attorney; as a consequence he's a wanted fugitive who can never return to his home.
He is a disturbed man, shaken by the death of his wife and the events that led him to leave his children. Cobb struggles to leave his dark and tortured past behind him, which is why he accepts Saito's offer. As time progresses, Cobb is forced to deal with Mal's projection until he is able to fully overcome her death.

Quotes: "You create the world of the dream. You bring the subject into the dream and they fill it with their sub-conscious."
"Well, dreams, they feel real while we're in them, right? It's only when we wake up that we realize that something was actually strange."
"Building a dream from memory is the easiest way to lose your grasp on what's real and what is a dream."