Sisyphus was a character in Greek mythology who upset the gods with his extraordinary wisdom. As punishment, he was sentenced to be blinded and to perpetually roll a giant boulder up a mountain to the peak, only to have it inevitably roll back down the mountain into the valley.
Camus develops the idea of the "absurd man", the man who is perpetually conscious of the ultimate futility of life. This, he says, is the only acceptable alternative to the unjustified leap of faith which forms the basis of all religion (and even of existentialism, which Camus therefore did not fully accept). Drawing on numerous philosophical and literary sources, and particularly Dostoevsky, Camus describes the historical development of absurd awareness and concludes that Sisyphus is the ultimate absurd hero.
In his essay, Camus has Sisyphus experiencing freedom for the one brief moment when he has stopped pushing the boulder before he has to start back down the mountain again. At that point, Camus felt that Sisyphus, even though blind, knew the view of the landscape was there and must have found this uplifting: "One must imagine Sisyphus happy", he declares. Returning to his original question, he concludes that suicide is never justified.
Camus presented Sisyphus' ceaseless and pointless toil as a metaphor for modern lives spent working at futile jobs in factories and offices. Some people find this metaphor comforting, since it makes them feel they are not alone, and indeed can draw a parallel between their life and the life of a character from the dawn of time.