A strong field of some 80 current and former Olympic medallists will be competing in Doha, all with an eye on securing a good start before Brazil and, in some cases, imminent qualifiers ahead of Rio.
In total, eight Olympics gold medallists will compete, as well as more than 40 athletes with World Championship medals.
Much of the focus in Doha could fall on Kenyan stars, especially the middle-distance events.
Almost 30 Kenyan athletes are expected in Doha, and as many as eight could run in the men's 1500m.
Among these are Asbel Kiprop – though he may drop down to the 800m on Friday – Elijah Manangoi and Silas Kiplagat.
Kiprop is the 2008 1500m Olympic champion and also three times a World Champion over the same distance.
He has already stated that Olympic gold is his aim for the year.
Manangoi is a former world silver medallist over 1500m and is competing in just three races before the Olympic trials.
Kiplagat, meanwhile, is the second fastest man in the field, behind Kiprop.
In the 3000m steeplechase, Kenyans Ezekiel Kemboi and Conseslus Kipruto – rivals and training partners – head a strong field.
The women's 100m includes the Netherlands' Dafne Schippers, who recently took silver at the World Indoors 60m, and Jamaica's Veronica Campbell-Brown, the 200m Olympic gold medallist in Beijing.
