What is it about the 100m final? Why does it focus the world's attention so sharply? Track fans will tell you it is the essential expression of sport, the most elegant of all competitions, a place where the third world can take on the first world and win on merit alone. The hundred requires no equipment, no swimming pool, no carbon fibre bicycle, not even a ball or a net. It subtracts everything extraneous and leaves behind only the body and one task it must perform. Some say it functions as a metaphor for human endeavour itself. As the record time gets ever lower it seems like we must be progressing, but what other kind of truth might be hidden here in a test that, at least on the surface, appears so simple and so clear? How are we linked, the participants and the couch potatoes, the athletes and the spectators?

These are the questions that circulate inside and around Richard Moore's The Dirtiest Race in History. He takes us back 24 years to a September afternoon in Seoul. Carl Lewis and Ben Johnson are linked in memories of an infamous contest and well-known to even the most committed non-sports fan. Lewis, the owner of nine Olympic gold medals  four golds won in four different Games  was named "Athlete of the 20th Century" by the IOC, the IAAF, and Sports Illustrated. At the other extreme, any 1988 photograph of Johnson  with his acne, his bloodshot eyes and hulking physique  can stand as an iconic representation of what a disgraced, steroid-engorged cheater is supposed to look like. By the end of his career, Johnson was banned from competition for the rest of his life and stripped of all his medals, titles and world records.

Written with a fine sense of balance, timing and tension, The Dirtiest Race follows these rivals along their intersecting trajectories. Lewis, the product of a stable, middle-class American family, is portrayed as an attention seeking diva, a man who always believed he was bigger than his sport. At the 1984 Games in LA, his manager even boasted that Lewis would be "as big as Michael Jackson". Though his once-in-a-generation talent is undeniable, he never really captured the American imagination, and as he moved on to his second act, he made a series of cringeworthy decisions to re-invent himself first as a singer and then an actor and then as a politician. In contrast, Johnson is the poor Jamaican immigrant to Canada, a man rapturously embraced, then harshly rejected by his adopted country. Though he possessed the greatest explosive start in the history of track and field, he also suffers from a debilitating speech impediment that triggers in times of stress. The two men couldn't be more different, the stutterer and the wannabe politician. Lewis's running is described as graceful and beautiful while Johnson's is powerful, almost violent. Moore tells us the Canadian boasted of his conquests as a womaniser, while the American dodged rumours of homosexuality. After Seoul, Lewis flourished and Johnson lost almost his entire fortune. When he returned home to Toronto, he found that contractors had already walked away from his half-completed mansion. His fast cars were repossessed, and he ended up living in his mother's basement for many years. Later, while Lewis was recording and acting, Johnson was participating in humiliating carnival-type races, in which he lined up against racehorses and stock cars.

Johnson's and Lewis's hatred for each other is stamped on nearly every page of this book, but the real strength of Moore's account is his depiction of the secondary characters, a cast of megalomaniacal managers and coaches who seem inspired by Victor Frankenstein to push the limits of science and the human body. There are plenty of shady doctors and duplicitous friends and disloyal team-mates. There are impotent drug testers, self-serving bureaucrats, egotistical sport executives and a parade of agents, journalists, lawyers and strange spiritual gurus. All of them are connected directly or indirectly to the events in South Korea; all were, in different ways, set to benefit from the Games. Moore is right: this was a dirty race and as the story unfolds, it gets harder to tell the heroes from the villains. We often find ourselves confronting confessed cheaters who seem refreshingly honest or champions who raise our suspicions.

Followers of Linford Christie or Mark McGwire or Marion Jones or Roger Clemens or Lance Armstrong will recognise this confusion. How should we react when a hero reveals, or refuses to reveal, that he or she is merely human? And what do we do with the dishonest victor who may or may not have used one powerful lie to raise billions for cancer research? When the Canadian judge, Charles Dubin, called his "Inquiry into the Use of Drugs and Banned Practices Intended to Increase Athletic Performance" he found that world-class competition appeared to take place in an "ethical vacuum". He warned: "We cannot allow sport, which we expect to build character, to become a means of destroying it."

While Johnson meets with Moore and shows him around Toronto, even taking him to a training session where he coaches young children, Lewis, perhaps sensing that no good can come of it, declines all invitations to participate in the project. Moore gets to meet him only once, in 2010, during a general press junket to open a new Nike store in London. It is perhaps the most revealing moment in the book, and Moore handles it masterfully. When Lewis is asked for a comment about Usain Bolt's record-breaking performances, he hesitates, as though, even now, he cannot bring himself to compliment another runner.

Bolt doesn't fit the mould of the scowling, macho sprinters of the 1980s and 90s. He is not Maurice Greene and he has no angry rival. This is the runner who started celebrating 20 metres before the finish in Beijing and still came flying across the line with his arms open wide and the cocky exuberance of kid who can't believe his luck. Though he is the best the world has ever seen, Bolt makes it look fun, with his laughter, his disco dancing, and his lightning pose. He is a marketer's dream. Nine and half seconds of Bolt's life may earn him more money than Lewis and Johnson made in their entire careers combined.

Yet everybody knows his night will come eventually, and perhaps no man on earth understands his situation better than Carl Lewis. At the Nike store, the champion of 1984, '88, '92 and '96 could not give in to the general euphoria. "It's just ... interesting," Lewis said. "I watch the results like everyone else and wait ... for time to tell."

 Alexander Macleod's Light Lifting is published by Jonathan Cape.