Tirunesh Dibaba wins the 10,000m in Eugene (Kirby Lee - Image of Sport) © Copyright
Four years ago in Beijing Tomasz Majewski surprised the Americans by taking gold in the Shot Put, and the Pole is back to defend his title. But the man to look for is Germany's David Storl, who landed a surprise gold at the World Championships in Daegu last year.
Storl has produced his four best ever throws at major championships, and he'll once again need to be in the form of his life as he takes on a stellar field.
World leader Reese Hoffa is undefeated since April, taking the US title with 22.00m and backing it up with victory at the London Diamond League with 21.34m.
US team-mate and 2009 World champion Christian Cantwell is always a huge threat, and he will have the accolade of being the first track and field athlete to compete at the London 2012 Olympics as he is first up to throw in his group.
Ryan Whiting was a surprise winner of the World Indoor title, and if he brings that 22-metre form to London it would be enough for a medal, perhaps even gold, while Canada's World silver medallist Dylan Armstrong will be keen to make the podium in London after narrowly missing out in Beijing.
But before any of these contenders battle it out for the medals in the evening session, they will first have to make it safely through qualifying – the first event of the morning session. It has been known for many a big favourite to falter in qualifying, so nothing is a guarantee.
Will Dibaba successfully defend 10,000m title?
Tirunesh Dibaba has had a few injury-hit years since winning the distance double at the Beijing Olympics, but the Ethiopian is back in form and ready to defend her 10,000m title.
She won't have it easy though, as double World Champion Vivian Cheruiyot is in the field and the Kenyan hasn't been beaten on the track for almost two years.
Team-mate Sally Kipyego was Cheruiyot's closest challenger at the World Championships last year, and she looks more than capable of making it on to the podium again in London.
Other contenders include Dibaba's team-mates Worknesh Kidane and Belaynesh Oljira, but if anyone can break up the African dominance then perhaps look to Russia's Elizaveta Grechishnikova or European Cup winner Sara Moreira of Portugal.
London 2012 poster girl Ennis begins eagerly-awaited Heptathlon campaign
The women's Heptathlon also gets underway and Britain's Jessica Ennis will be hoping to get off to a good start in front of a home crowd. Earlier this year she set a national record of 6906 – a mark that has only been bettered by Carolina Kluft in the past 20 years.
The first four events of the Heptathlon will be contested on Friday and Ennis will want to have the overnight lead. But if World champion Tatyana Chernova is within touching distance of Ennis, then it could make for an interesting second day of competition as the Russian excels in the final three events.
The preliminary round and heats of the women's 100m will take place as Shelly-Ann Fraser begins her title defence. Expect to hear huge roars from the home crowd when the likes of Dai Greene competes in the 400m hurdles heats and Christine Ohuruogu goes in the first round of the 400m.
The men's 3000m Steeplechase and 1500m events also get underway, as Kenya set out to achieve a clean sweep of the medals in both events – provided they all make it through the heats, of course.
Fans will also be treated to a rare glimpse of the two current global champions in the men's Hammer Throw who rarely compete on the circuit – Olympic champion Primoz Kozmus and World champion Koji Murofushi. Between them, the pair have competed just three times this year. Whether that preparation will be conducive to qualifying for an Olympic final will all be revealed.
There will be plenty of other field event action too as athletes look to qualify for the finals in the women's Triple Jump, women's High Jump, women's Discus Throw and men's Long Jump.
Jon Mulkeen for the IAAF
Click here for timetable, start lists and results