A mass of sweating angry men storm New York City's summer streets, breaking windows and stealing property, murdering people with different skin colors and beating others whose clothing suggests middle-class comfort.

That racial riot in Peter Quinn's Banished Children of Eve a new novel that provides a detailed context for the four days in July 1863 when New York City exploded into a bloody riot.

"I believe in history that there's only been one mob, and all mobs act the same way," Mr. Quinn said in an interview as he compared the New York draft riots of 1863 to the riots in Los Angeles in 1992. "The reptilian brain somewhere on the evolutionary scale takes over, and when people go berserk for whatever reasons they do the same thing."

The mob in Mr. Quinn's novel and in history's record of the draft riots was mostly made up of impoverished Irish people rebelling against conscription into the Union Army during the Civil War. As they poured into the streets from tenements and shanties along the Hudson River, they not only burned and looted stores and homes, but also murdered any black person they could lay hands on and a few military men as well.

Records verify 119 deaths. Some historians estimate that up to 1,000 people died and property losses ran $1 million to $2 million.

Banished Children of Eve, a 612-page first novel, portrays the tensions between working-class blacks, who had been freed by the New York antislavery law of 1799, and the Irish, who, along with 2.1 million of their countrymen, had recently fled death and famine in Ireland.

As the two groups competed for low-paying jobs, the Irish used their skin color to push blacks out of their way. The paradox, Mr. Quinn said, is that the two groups had more in common than they realized.

"Irish culture was a popular culture," he said. "It was a folk culture that resided in music, dance and storytelling, which is what black culture was in the South."

Both groups, he said, transmitted the traditions through the church and music and both spent generations farming land that did not belong to them.

Writing in The Boston Globe, Kevin Cullen called Mr. Quinn's book "a compelling account of how those at the bottom inevitably turn on one another, rather than join forces to challenge whomever or whatever it is that has kept them down."

Mr. Quinn said many Irish-Americans did not realize that their ancestors were social outcasts. "Almost every person in the establishment of New York in the middle of the last century was horrified by Irish immigration, from Herman Melville to Charles Loring Grace to Frederick Law Olmstead," Mr. Quinn said. "The only one who wasn't was Walt Whitman."

That may explain Mr. Quinn's use of a quotation from "Leaves of Grass" at the end of the book. It reads: "Each belongs here or anywhere as much as the well off … just as much as you. Each has his or her place in the procession."

Mr. Quinn shares another affinity with Whitman. Both were regular visitors to Greenport. "Walt Whitman's sister lived in Greenport," Mr. Quinn said. "He used to take the train out, and it took three and a half hours. So some things don't change."

Mr. Quinn, who was born in Greenport 46 years ago and raised in the Bronx, lives in Brooklyn with his wife and two children. His family owns a house on Shelter Island and regularly makes their way there through Greenport.

His parents were vacationing on Shelter Island the summer when he was born. "The doctor took an X-ray, and when he saw two tiny spines he put my mother in what was then the Greenport Hospital," Mr. Quinn said, explaining that he has a twin brother.

The author's interest in Civil War New York began when he was working as a speechwriter for Gov. Mario M. Cuomo and received a copy of "Armies in the Streets," a history of the draft riots. "In the back of it was a list of people killed, and one of them was Peter Quinn," Mr. Quinn said.

He began collecting pictures of mid-19th century New York City. "They all looked like South Street Seaport," he said. "You know, quaint."

When Mr. Quinn came across a copy of the first housing report to the State Legislature, he realized, he said, the "incredible squalor and misery" suffered by some people in that era.

The report documented "back-lot tenements, basements filled with people, no plumbing, no air," Mr. Quinn said. He started trying to recreate the lives of people forgotten not only by history, but also by the period fiction and seen in books like Henry James's "Washington Square."

Mr. Quinn researched his project for six years. He organized the information in notebooks in sections for each character. When he started writing, making up stories to go with the material came naturally, he said, adding:

"As a kid growing up in my family it was important that you could speak at the dinner table and tell stories. Speeches that work tell stories. Speeches that don't work are dead rhetoric."

He is now chief speech writer at Time Warner Inc.

Banished Children of Eve details characters of different races and classes, most fictional but some nonfictional. Stephen Foster, past his creative prime, stumbles in and out of the novel in a drunken stupor, the notes of scores and visions of the future music industry circulating in and out of his consciousness.

"Stephen Foster is a lot like Elvis," Mr. Quinn said. "He brought black music to white people, because they wouldn't take it from black people." The Irish, he said, did the same thing when they put on black face to perform in the minstrels.

In Banished Children, Mr. Quinn uses the theater as a symbol of how the races can get along if they share a common vision. A cunning mulatto woman, Eliza, finds her way out of a high-class brothel and into work as an actress in a presentation of Uncle Tom's Cabin. Her lover, Irishman Mulcahey, who survived the crossing of the Atlantic during the Potato Famine, becomes a minstrel performer through sheer will, Mulcahey's other closest friend is his black assistant, Squirt.

Drive and ambition are what the characters in Mr. Quinn's book share, regardless of their class and race. Spunk and exceptional resourcefulness, intermingled with a necessary callousness, often spell the difference between not only the characters' success, but also their survival.

There are a farm boy from Southampton who erases his past and eventually heads a Wall Street brokerage, an Irish teen-ager who ignores adult advice and lies her way into a maid's position in a "good house," an Irish-born con artist and petty burglar who finally establishes himself in a "legitimate" saloon and an elderly female fishmonger who uses will and feigned madness to keep her fish stall, the only one owned by a black person on Fulton Street.

As the portraits emerge and the stories intertwine, water becomes a symbol for a social rank. The broker knows that he has truly made it when the house he buys for his bride has flush toilets. "People's access to water—that was the real divide between the comfortable and the uncomfortable," Mr. Quinn said. "You could hook up to the Croton system for $10 a month. That means you didn't have to go to the privy in the yard."

Another liquid that flows steadily through Banished Children is low-quality liquor, which, Mr. Quinn points out, parallels the drugs in inner cities today. "We don't think of it as substance abuse," Mr. Quinn said of the alcohol that his characters consume. "But it really was the poor anesthetizing themselves against their poverty."

Mr. Quinn said a chief interest in writing the book was to convey the complexity of history that is lost in its retellings by the ruling classes. That helps explain Audley Ward, a comical figure who, despite his financial decline and need to rely on his son-in-law's "new money," spends most of his time writing essays that ennoble his family's history and confirm their aristocratic superiority.

Ward is obsessed with the notion that the size of the English cranium is larger than that of both the Irish and the blacks.

Banished Children of Eve ends with fictional historic documents that Mr. Quinn said purposefully erased the impoverished, black and female characters that he took such pains to create. "In the epilogue women and blacks disappear," he said. "Their history is totally lost and never recorded."

Mr. Quinn counts among the "banished children" all who have been deprived of fertile ground on which they might have thrived. The words are taken from a Roman Catholic prayer imploring the Virgin Mary.

"To thee," it says, "we cry poor banished children of Eve, to thee we send up our sighs, mourning and weeping in this valley of tears."

Mr. Quinn said he wrote Banished Children of Eve in three and a half years, working weekday mornings from 7:15 to 9:15. Part of his inspiration came while crossing the East River on the subway from Brooklyn. He said he would look down on South Street, where his ancestors probably landed when they arrived here.

"Taking that train every morning was part of my writing," he said. "Writers hope for some kind of grace, and that to me was mine."

Mr. Quinn is now working on a novel that focuses on a murder in September 1938. "It's about the Bund, a Nazi camp in Yaphank," he said. "It's about eugenics, selective breeding and forced sterilization of the retarded, which I think is one of the most horrific movements of the 20th century. The Eugenics Record Office was in Cold Spring Harbor."