Endless hours of research at the Library of Congress left Kenneth Ackerman in a world of feuding characters, fierce battles of power and a dramatic presidential odyssey during the Gilded Age.

“Half the time I don’t know what century I’m in,” said Ackerman, who for years studied the post- Civil War era in preparation for his book “Dark Horse: The Surprise Election and Political Murder of President James A. Garfield.”

“You spend a lot of time on the characters,” Ackerman said. “When you go to the movie or hear a joke, you wonder which one would find it funny. You feel like you live with the person.”

After more than six years of research and writing, the historical figures of Ackerman’s research came together to tell the story of Garfield’s election and subsequent assassination.

“Dark Horse,” Ackerman’s second book, was released July 2, marking the 122nd anniversary of Garfield’s death. The publication set off a series of marketing campaigns in which the 1973 Brown University graduate also met 12 descendants of Garfield’s family in Mentor, Ohio, who were “very pleased” with the book.

Ackerman, who was able to work part-time at Ollson, Frank and Weeda PC while writing his book, said he “neurotically” read reviews of his book.

To his bemusement, Ackerman, who is a 1976 graduate of Georgetown University Law Center, discovered that Amazon.com displayed hourly updates on the book sales rankings — a finding that led him to “follow” the sales in the summer, he sheepishly admits.

Ackerman was able to create relationships with his characters after research at the Library of Congress and the Senate Historical Office, among others.

“Researching Garfield was easy because he wrote obsessively,” Ackerman said of the former president’s four volumes of diaries.

“There’s a lot of material where he expresses himself,” he said. “His writing says more about him than what he writes.”

For others, Ackerman was able to explore their personalities through remnants they left behind, such as bills from tailors and hotel bar tabs.

Other characters, such as Sen. James G. Blaine (R-Maine), presented a challenge to Ackerman, because Blaine went through his papers and “cleansed” sensitive materials — something Ackerman suggested politicians don’t do.

“If you view the world through eyes of world today, you take away voice from history,” he said.

Ackerman served more than 25 years in senior posts on Capitol Hill and in the executive branch, as counsel to the Senate Governmental Affairs Committee under then-Sen. Charles Percy (R-Ill.), and later as special counsel to the Senate Agriculture, Nutrition and Forestry Committee under its then-chairman, Sen. Patrick Leahy (D-Vt.).

Ackerman’s history on the Hill allowed the Albany, N.Y., native to draw interesting parallels between the Gilded Age and today.

Garfield’s “dark horse” campaign, his victory in a close popular vote for presidency, his struggle against feuding factions, and the public’s response to its violence, sets a revealing resemblance to current political themes.

“This is a story about factionalist bitterness going out of control,” he said, adding that the animosity in the late 20th and early 21st century between Republicans and Democrats was “very reminiscent” of the Gilded Age.

Next to being a cautionary tale, “Dark Horse,” named after the term for a political candidate who unexpectedly becomes a candidate at the convention, also demonstrates the aspects of the political process that are in danger of fading away today.

“The human scale is something that we are in danger of losing today,” the self-described politics junkie said.

In contrast to recent presidential elections, 80 percent of voters participated in Garfield’s run on the White House in 1880, when things such as television, radio, and the NFL didn’t exist, according to Ackerman.

“There was an electricity [in the air], the same energy that people bring to the World Series now, for example,” he said. “Then, politics was the national soap opera. Politics [in the 1880s] was so personal; it’s something you don’t see today.”

Several hundred pages of text on Garfield and his politics may seem like a stretch, but Ackerman asserts a human story is at the core of the book.

“It is a story of a decent person thrown into a difficult situation,” Ackerman said. It is a story about someone who had an abstract daydream to be president, realized it wasn’t easy and ended up making a pact with the devil, he said.

After observing “scripted and dull” political conventions in 1996, Ackerman became interested in writing about an era when “conventions really mattered.”

Ackerman was familiar with the 1880s from his first book, “The Gold Ring: Jim Fisk, Jay Gould, and Black Friday 1869,” and stumbled across Garfield’s story and was intrigued. A short guest column in Roll Call about the mid-session Senate flip from Republican to Democratic control in 2001 rendered itself as a comparison to Garfield’s era, and resulted in a book proposal that was eventually picked up by Carroll and Graf Publishers.

“Ken wrote a terrific proposal,” Philip Turner, executive editor at Carroll and Graf. “This book is so readable. He really makes 1880 and 1881 come alive.”