Kenya's Ronald Korir and France's Martha Komu head the fields for the Harmony Geneva Marathon,, an IAAF Bronze Label Road Race, on Sunday (8).
Korir, 25, is the class of the men's race, boasting a 2:07:29 personal best, which he ran to finish sixth in the Frankfurt Marathon in 2014.
This will be his second marathon this year, having finished fourth in the Marrakech Marathon in January in 2:12:59. Since then, Korir has dropped down to shorter distances, racing over 3000m and 5000m in the USA, where he is based.
His biggest opposition on Sunday may come from his Kenyan compatriot Julius Chepkwony, who ran his personal best of 2:09:00 to finish sixth in the 2014 Daegu Marathon. The 30-year-old was a winner at the Venice Marathon last October in 2:11:08, but this will be his first major race of 2016.
The athlete with the best chance of upsetting the Kenyan duo is Ethiopia's Shume Hailu, who was runner-up at this race last year in 2:11:27. His best time of 2:09:06 dates back to 2011, but Hailu has experience in winning marathons at this level, having won the Rome Marathon in 2014 in 2:09:47.
Nixon Machichin is another who, at his best, looks capable of taking victory here.
The Kenyan has a best of 2:08:22, which he ran to finish fifth at the Toronto Marathon in 2010. More recently, he was a winner at the Lyon Marathon in 2015, running 2:10:14.
Of the rest, Kenya's Emmanuel Sikuku and Ronny Kiboos look the most likely to challenge for a place on the podium and maybe the title.
Sikuku's best result was when finishing fourth at the 2014 Zurich Marathon, running 2:11:20, and he holds a half marathon best of 1:01:37, run in Udine, Italy, three years ago.
Kiboos is a 2:12:08 marathoner at his best, which he ran to finish second at the Hefei marathon in China two years ago.
Komu the class of women's field
In the women's race, the athlete with the best overall credentials is Martha Komu, of France, who has a best of 2:25:33, which she ran to win the Paris Marathon in 2008.
Komu went on to finish fifth in the Olympic marathon in Beijing that year, but the 33-year-old been well off her best in recent years, her strongest effort being a 2:33:33 run in Paris last year.
A more likely winner may be Kenya's Jane Kiptoo, who returns to Geneva looking to defend the title she won last year.
The 33-year-old is a 2:31:08 performer at her best, which she ran to finish second at the 2014 Sydney Marathon. Kiptoo also boasts a half marathon personal best of 1:09:07, dating back to the Lisbon Half Marathon in 2009.
Her main challenger on Sunday is likely to be fellow Kenyan Ednah Kimaiyo, who has a best of 2:31:25, which she ran to finish second at the Rennes Marathon last year. The 28-year-old has yet to race this year, but was a prolific racer in 2015 and won three of the five half marathons she contested, lowering her personal best to 1:10:45 in Nice last April.
Ethiopia's Roze Dereje and Tesfanesh Denbi are also likely to be in contention. Dereje has a best of 2:34:04, run at the Algiers Marathon last year, while Denbi has a best of 2:34:44 from her third-place finish at the Dublin Marathon last year.
An interesting debutante is Kenya's Helen Jepkurgat, who has a half marathon best of 1:09:56, run to finish second in Piaccenza, Italy last year. She proved preparations for her marathon debut are progressing well when finishing third at the Milan Half Marathon in 1:11:34 back in March.
Cathal Dennehy for the IAAF