With two loaded, miniature golden pistols in his pocket, John Boswell stalks the streets of 18th-century London in pursuit of two men: his brother James and author Samuel Johnson. That hunt drives The Brothers Boswell, a new novel from English professor Philip Baruth. The literary thriller explores a specter in the otherwise well-documented life of writer James Boswell: his insane brother, John.

Research for the story began when Baruth was just an undergrad, reading James Boswell's London Journal for the first time. Boswell was 22-years-old when he wrote the journal, which chronicled his time in the English capital - the same age as Baruth when he began reading it. "His father wanted him to be a lawyer, and my father wanted me to be a lawyer. And Boswell didn't want to do it, and I didn't want to do it," Baruth says with a grin. "So I felt this immediate kinship with him, and that has persisted throughout the years."

Their similarities end short of Boswell's womanizing and heavy drinking, Baruth is careful to note. But even the writer's many character flaws cannot strip him of his literary genius, Baruth adds, or as a primary source of knowledge we have today about 18th century life - details derived both from Boswell's celebrated biography of Samuel Johnson and also from 14 volumes of his autobiography discovered in the 1920s.

While those details allowed Baruth to forge a connection with a writer some 300 years his predecessor, they also posed a problem. "When I went to write a novel about him, I really knew too much because he lays his life out that year in methodical grid-like detail," Baruth notes. "You can literally chart his progress around London using his diary. And that doesn't leave a lot of room for imagination."

A narrative opportunity presented itself in the form of Boswell's younger brother, John, who showed up in London unexpectedly after leaving the mad house, just as James was quickly climbing the literary and social ladder. "The more I read (the journal), the more it seemed that Boswell was horrified, in a certain way, that he had shown up at a time when Boswell was just breaking through all these social barriers," Baruth says. "So here's the crazy younger brother who has the ability, unless things are managed, to ruin it all."

That tension is the heart of Baruth's novel. By casting John as narrator, Baruth carves out a space to tell a story about brotherhood, madness, revenge and legacy - all within the framework of the unlikely and socially ambitious friendship Boswell formed with Johnson, a literary giant 31 years his senior. "The grid that Boswell laid out I leave as it is, and then I just have John move in and out of that," Baruth says, "and I create a story that's highly fictional but makes use of all that nonfictional material."

His use of the source material is a point of pride for Baruth, who was recently called to task on the book's historical accuracy at an Oxford conference celebrating what would be Johnson's 300th birthday. While no characters in the book do anything that contradicts what has been recorded of their lives, there is a good deal of improvising in the gaps, including insinuations about Johnson's sexuality. "One man actually started stamping his cane after I was done," Baruth recalls of an angry conference attendee who considered the novel "dangerous." Baruth's response? "Good fiction is dangerous; it has the ability to make you reconsider all of your most cherished ideas of the world."