Cooke, 25, has the strongest British team for years at her disposal, but faces strong competition from 2006 champion Marianne Vos.
But defending champion Marta Bastianelli tested positive for an illegal substance and was kicked off the Italian team.
Pooley, boosted by the withdrawal of reigning world champion Hanka Kupfernagel, will still have to overcome Olympic champion Kristin Armstrong.
KEY ROAD WORLDS FACTS
Elite men: 15 x 17.35km laps - 260.25km
Elite women: 8 laps - 138.8km
Under-23 men: 10 laps - 173.5km
Montello: 1.15km at 6.5% average gradient
Ronchi: 3.13km at 4.5% average gradient
Total climb: 3,632m (elite men)
Elite men: 46km
Elite women: 26km
Under-23 men: 35km
Favourite for the men's road race title is Italy's Paolo Bettini, who has the chance to make history by winning the event for a third consecutive year.
The 34-year-old knows the terrain well around Varese but will have to fend off the challenge of Oscar Freire and his powerful Spanish squad, which includes Vuelta Espana winner Alberto Contador, Olympic champion Samuel Sanchez and UCI ProTour winner Alejandro Valverde.
British hopes rest with Steve Cummings, second in the Tours of Britain and of Denmark, and David Millar, with back up coming from Geraint Thomas, Ian Stannard and Chris Froome.
The event will be an important early milestone in British Cycling's nascent plans to transfer dominance on the track to the road.
Cummings also goes in the men's time trial, which is wide open following the withdrawal of reigning champion and Olympic gold medallist Fabian Cancellara.
The Swiss rider pulled out citing fatigue in the wake of his time trial victory in Beijing.
Cummings was a very creditable 11th in Beijing but would have been a stunning fourth had his chain not come off.
Great Britain's Sharon Laws introduces you to cycle racing on the road
Favourites include Australia's Michael Rogers, who has the chance to win an historic fourth gold medal after a hat-trick of wins between 2003 and 2005, and USA's Levi Leipheimer.
The six-day competition is contested by national rather than trade team and features a time trial and road race in each of three categories - elite men, elite women and under-23 men.
The winner of each event earns the right to wear the world champion's rainbow jersey for a full year.
The British under-23 squad, which is based in Tuscany, goes into the championships as perhaps the strongest team.
Both Ben Swift and Peter Kennaugh have notched up notable wins in Italy already this season while Jonny Bellis is hoping to improve on his bronze medal in last year's Worlds.
WORLD CHAMPIONSHIP SCHEDULE
Tuesday 23 September - Under-23 men's time trial
GB squad: Alex Dowsett, Russell Hampton
Wednesday 24 September - Elite women's time trial
GB squad: Emma Pooley, Sharon Laws, Nicole Cooke
Thursday 25 September - Elite men's time trial
GB squad: Steve Cummings, David Millar
Friday 26 September - Under-23 men's road race
GB squad: Ben Swift, Peter Kennaugh, Alex Dowsett, Jonny Bellis, Jonny McEvoy
Saturday 27 September - Elite women's road race
GB squad: Nicole Cooke, Emma Pooley, Sharon Laws, Jessica Allen and Lizzie Armitstead
Sunday 28 September - Elite men's road race
GB squad: David Millar, Chris Froome, Steve Cummings, Russell Downing, Ian Stannard and Geraint Thomas
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