Frederick's Republicans and Democrats go to the polls today to choose candidates for mayor and the city's Board of Aldermen in what has been a lively and occasionally combative primary campaign.

The field includes five mayoral candidates and 15 contenders for the five-member Board of Aldermen.

On the Democratic side, Jennifer P. Dougherty, the city's first female mayor, is seeking a second term. Her challenger is former four-term mayor Ronald N. Young.

The showdown between allies turned enemies has perhaps drawn the most attention, and the finish is expected to be close.

Dougherty, 44, who owns two businesses in town, has campaigned as a tough, results-minded administrator who has checked uncontrolled growth, addressed chronic water shortages and boosted business. She has depicted Young as part of a good old boys network, implying two weeks ago that a link existed between him and the notorious "black book" scandal involving a prostitution ring.

Young, who became the youngest mayor in the city's history in 1974, has promised to restore civility to political discourse, saying the mayor's iron-fist demeanor has inflamed conflicts and sullied the city's reputation. The black book allegations, he said, are proof of her win-at-all-costs style. Although Young was not mayor at the time of the scandal, an alleged prostitute told police that the ring's leader had threatened to name him and other prominent figures if her operation was raided.

Young, 64, is the part-time administrator for the town of Indian Head in Charles County and has served in state government.

In the Republican mayoral primary, Joseph W. Baldi, 58, is trying to advance from his seat on the Board of Aldermen. Two newcomers -- William Jefferson "Jeff" Holtzinger, 41, a former engineer, and Stanley C. Mazaleski, 71, a former scientist -- have challenged him.

The election is open to about 24,000 voters who are registered in one of the two major parties. Polls will be open from 7 a.m. to 8 p.m. City Hall will serve as the returns center. Results will be posted on the city's Web site and aired by the local cable television station.

The location of polling places can be found on the city's Web site, www.cityoffrederick.com/election.