An Unlikely Union tells the dramatic story of how two of America’s largest ethnic groups learned to love and laugh with each other after decades of animosity.

They came from the poorest parts of Ireland and Italy and met as rivals on the sidewalks of New York. Beginning in the nineteenth century, the Irish and Italians clashed in the Catholic Church, on the waterfront, at construction sites, and in the streets. Then they made peace through romance, marrying each other on a large scale in the years after World War II.

The vibrant cast of characters features saints such as Mother Frances X. Cabrini, who stood up to the Irish American archbishop of New York when he tried to send her back to Italy, and sinners like Al Capone, who left his Irish wife home the night he shot it out with Brooklyn’s Irish mob. The book also highlights the torrid love affair between radical labor organizers Elizabeth Gurley Flynn and Carlo Tresca; the alliance between Italian American gangster Paul Kelly and Tammany’s “Big Tim” Sullivan; heroic detective Joseph Petrosino’s struggle to be accepted in the Irish-run NYPD; and the competition between Frank Sinatra and Bing Crosby to become the country’s top male vocalist.

In this engaging history of the Irish and Italians, veteran New York City journalist and professor Paul Moses offers a classic American story of competition, cooperation, and resilience. At a time of renewed fear of immigrants, An Unlikely Union reminds us that Americans are able to absorb tremendous social change and conflict—and come out the better for it.