The tagline for director John Schlesinger's "Marathon Man" read simply "A Thriller"--and so it is, despite a heavy sag of masochistic weight in its midsection. Dustin Hoffman looks in great shape playing a Columbia grad student, still haunted by his father's suicide (and perhaps in training for the New York marathon), who gets mixed up by proxy in his nefarious older brother's activities; seems his sibling has been working secretly as a courier in stolen gems, and has run afoul of Szell, a.k.a. The White Angel, the most notorious Nazi war-criminal still alive. Schlesinger shows off a nasty side of himself, staging some dental torture scenes that are just about impossible to watch; even worse, not all of the pieces in William Goldman's adaptation of his bestseller fit accordingly. Both men eagerly press ahead so that the story gaps won't be so noticeable, and there's much zig-zagging across the continents leaving red herrings, street bombs, and character intricacies in the picture's wake. We learn so little about Hoffman's brother (played by an equally fit Roy Scheider) that, by the film's climax, we still don't know whose side he was he on--or why his cohorts lost trust in him. Marthe Keller's mysterious German beauty is another character muddle, a pretense of writer Goldman who was really out to stack this deck against Hoffman's runner. Laurence Olivier's knife-wielding Nazi beast is perplexing as well, alternating a steely coldness with an aged confusion (why, for instance, is he staking out jewelry stores just for today's market values--isn't the diamond trade this man's forte?). "Marathon Man" needed less torture scenes (which aren't really suspenseful as much as they are excruciating) and more clear-headed chess moves. It leaves a bushel of questions behind, though it is a handsome piece of work, well-cast and with an intrinsically satisfying finale. **1/2 from ****