ST. PAUL -- The books are dog-eared, marked up and full of paper tabs holding certain pages.
The Al Franken best-sellers sitting on a shelf in a Minnesota Republican Party office were key materials GOP staffers turned to as they started compiling information about the comedian-turned-Senate-candidate.
While opposition research -- and the long-forgotten facts, statements, and video clips it can yield -- certainly is nothing new in political campaigns, it is a major factor in the contest so far between Franken and Republican Sen. Norm Coleman.
And the state parties -- the GOP and the Democratic-Farmer-Labor Party -- have played integral roles in collecting and dispensing information on the opposing party's candidate, whether Democrats criticize Coleman's voting record or Republicans point to Franken's tax problems and expletive-laced rants captured on video.
The Republican Party's research into Franken started long before he announced his Senate run in early 2007. Gina Countryman, the party's spokeswoman and former research director, said she started filing away news articles about five years ago when Franken first hinted he was considering a run.
The efforts were ramped up shortly after the 2006 election cycle. "He was one of a couple of candidates making noise at the time, so we started with him right away," Countryman said.
Between five and 10 party staffers and interns researched Franken. That included reading five Franken books -- the GOP paid for used copies -- and looking for passages to help bolster Republican claims that Franken has a pattern of disturbing behavior and staking out policy positions most Minnesotans oppose.
Not all attempts to bring up issues from Franken's past have garnered lots of attention, but state GOP Chairman Ron Carey said they have tried to create an "underlying impression" of Franken among voters.
"While they may not be front and center in the press, these things have made a mark on people's minds," he said, "and in the final days when they're trying to make those decisions, that will form part of the basis of how people will decide."
The Democratic-Farmer-Labor Party has done its own share of research into Coleman's background over the years. That research largely has been focused on his record in office, DFL spokesman John Stiles said.
"We think that Norm Coleman's public record as an elected official is more than enough to go on to make the case against him," Stiles said.
Democrats have "hundreds and hundreds" of pages of research on Coleman, he added.
Experts say opposition research used in ads critical of an opponent can influence an election, and is deployed more often in close races, such as Minnesota's Senate contest.
Paul Goren, a University of Minnesota political scientist, said those ads target independents and voters who lean slightly toward one party or another.
"It's not hard to imagine some of them being swayed by the negative advertising," said Goren, an expert on public opinion and elections.
Independence Party Senate candidate Dean Barkley says voters are being swayed toward his candidacy. Barkley, who served a brief term in the Senate in late 2002 and early 2003, said polls show he is benefiting from all of the mud-slinging between Franken and Coleman.
Franken has said all along that he expects Republicans will dig up old material from his previous career -- to try to draw attention away from Coleman's positions on issues.
"You present the record that the message supports," Countryman said. "This isn't spin, this is what his record shows."
Officials say the campaigns do some of their own research on the opponent and other groups -- including the campaign machines of Senate Democrats and Republicans -- also wage research efforts and create ads based on their finds.
Neither the state Republican Party nor the DFL Party has contracted with private firms to conduct research in the Senate race this year, officials from each party said.
"It's nice to have Minnesota eyes looking at this stuff," Countryman said.
Still, private firms know of the Minnesota contest.
"As a fellow opposition researcher, I have to say rarely am I blown away," Kevin Collins said. "This has been very, very impressive."
Collins, whose Washington-based Republican research firm Gallagher Hollenbeck is not working in Minnesota this year, said if he researched Franken, he would look for "outlandish things that he's said or written, but after a while you can't simply rely on the outlandish."
It also is important to highlight positions the candidate has taken that contradict earlier statements, Collins said.
"Thirdly, the biggest thing that's being overlooked is some of the things he says are not senatorial," he said of Franken. "They're not statesmanlike."
But Austin, Texas-based Democratic researcher Jason Stanford said Coleman and Republicans are "in a box" with old Franken material.
"They not only have to educate people about the issues," Stanford said, but "they have to convince them to be upset about them."
Carey said there is no set strategy for when to release something unearthed through opposition research. A candidate's statement on an issue and the news of the day often dictate whether parties or campaigns release potentially damning material on an opponent.
And party officials were tight-lipped about whether they plan a mid-October surprise for voters.
"We'll see," Carey said in a coy tone.