RESPECTED, REVERED-AND EXPENDABLE Pain. Getting ripped off. Watching your potential wither on the vine due to contractual disputes that arise when people view you as their property. More pain. For the upper echelon of professional athletes in mixed martial arts, life can resemble the nightmare, described by Colonel Kurtz in Apocalypse Now, of a snail traversing the edge of a razorblade.Pound for Pound traces five legends-Georges St-Pierre, BJ Penn, Anderson Silva, Maurício Rua and Fedor Emelianenko-through their humble origins, baptism by blood and fire, and rise to the pinnacle of MMA, where the sword of Damocles constantly threatens.On the surface, we're conditioned to see these fighters as mere sports entertainers. We consume pay-per-views just as a diner patron drops quarters in a jukebox. Fighters' lives, however, are often more complex-and disturbing-than what event previews or color commentary portray.