Jamaica's Usain Bolt.
Training partner Yohan Blake beat Bolt over 100m and 200m in the Jamaican Olympic trails, but Bolt now appears fully fit and keen to win again.
"I've told Yohan Blake that 200 meters will be different, because that's my signature event. I'm not going to let him beat me again. I've said that to him already," Bolt said. "Remember I said that, Yohan."
The 200m heats are in the morning track session. The 200m semifinals are Wednesday, and the final is Thursday night.
More races
Another sprinter aiming to prolong her title is track cyclist Victoria Pendleton, who seeks to extend Britain's dominance at the London Velodrome in the individual sprint on the last day of track cycling.
If Pendleton reaches the final as expected, she will likely meet her longtime Australian rival Anna Meares for the pair's last race. Pendleton is retiring after the Olympics.
Chris Hoy competes in the keirin and could bring his personal Olympic gold medal tally to six if he wins, taking him beyond British rower Steve Redgrave.
Style rather than speed is the order of the day at Greenwich Park, where the 15-year-old German-bred mare Rafalca, co-owned by the wife of Republican Presidential candidate Mitt Romney is among horses and riders taking part in the team dressage competition.
Four gold medals will be handed out on the final day of the artistic gymnastics competition: Men's parallel bars and horizontal bar and the women's beam and floor.
The men's triathlon will see athletes swim, ride bikes and run around Hyde Park in central London two days after the women's race produced the closest of photo finishes at the end of a combined 1 500m swim, 40km bike ride and 10km run.
Back at the Olympic Stadium for the evening session, medals will be contested in the men's high jump, and discus, the women's 100m hurdles and the men's 1 500m. – Sapa-AP