More Jews once lived in Harlem than anywhere else in America.

In 1917, Harlem was home to the second largest population of Jews in America and the third largest in the world—about 175,000 strong. The Lower East Side and Warsaw were the only other communities that could claim more Jews than Harlem, with approximately 350,000 Jews and 343,000 respectively.

The author Gurock explains the demographics of the area: “In East Harlem, the Jews shared the neighborhood with Italians (Fiorelli LaGuardia was their District Leader and Congressman). In Central Harlem, the population was German—both Jewish and non-Jewish.”

“North of 125th Street was the early black enclave,” he says. As of 1920, 70 percent of Manhattan’s 107,000 Blacks lived in Harlem; in the 1920s an additional 175,000 moved in.

How the two groups got along is a complicated story. “There is no one Jewish story pre-World War II,” says Gurock. “There were some Jewish real estate operators in the early decade of the century who tried with their Christian counterparts to keep blacks out of the neighborhood. At the same time, pre-World War II, almost the entire white population in the black areas was Jewish. Jews showed no special disinclination to living with African-Americans.”

Before 1930 there were two distinct Jewish Harlems.

One was East Harlem (which Gurock defines as 96th Street and the East River to Fifth Avenue, north to the Harlem River); the other was Central Harlem (110th Street to 125th Street, Fifth Avenue to Morningside Avenue).“ The further you moved westward, the better you were doing.”

Gurock says that Central Harlem was the home of the hero of Abraham Kahan’s 1917 bestseller, The Rise of David Levinsky. The titular character was  a poor immigrant boy from Russia who made his way to America and the Lower East Side, became wealthy in the garment center, moved up to Harlem to an elegant apartment overlooking Central Park.

East Harlem was the home of a very different kind of Jewish family and the example Gurock chooses was quite real: Gurock’s own paternal grandparents. As he explains, they lived in a tenement at 100th Street and Park Avenue where their four sons shared one bed.

Two of present-day Harlem’s most imposing church buildings were once synagogues.

Central Harlem, before 1930, had 40 to 50 synagogues, some quite formidable; East Harlem had about 150 smaller ones. Those in Central Harlem that still stand have since been converted to churches but Jewish symbols are still visible on some of their facades.

Two of the most historically significant synagogues in the neighborhood stood across the street from each other on West 116th Street between Fifth Avenue and Malcolm X Boulevard. Ohab Zedek, which is now on the Upper West Side, is probably best known for hiring Yossele Rosenblatt,  the man considered to be the most famous cantor who ever lived. Rosenblatt appeared as himself in the first talkie movie, The Jazz Singer, after having refused to play the role of Eddie Cantor’s father.

The Institutional Synagogue was built diagonally across from Ohab Zedek, at 37 West 116th Street, and was the first synagogue in America to have a community center complete with a pool, an art room, and more. The founders’ intent,  according to Gurock, was to get people “to come to play and stay to pray”.

Ohab Zedek is now the Harlem Baptist Temple Church and the Institutional Synagogue is now the headquarters of the Salvation and Deliverance Church.

 Students at the Uptown Talmud Torah, circa 1917 (The Jewish Communal Register of New York City, 1917–1918).

Some the 20th century’s most prominent Jews lived in Harlem.

One of the first Jewish residents of Harlem was Benjamin Peixotto, sent in 1870 by President Ulysses S. Grant as his envoy to Bucharest and charged with expressing America’s antipathy to Romania’s persecution of the Jews.

Many of the other influential Jews who lived in Harlem in the first quarter of the 20th century were involved in one way or another with show business. The list includes Oscar Hammerstein I, cigar-maker-turned-Harlem-real-estate-developer who owned the Harlem Opera Theater on 125th Street and was the grandfather of Oscar H II, George and Ira Gershwin, Milton Berle, Fannie Brice and Sophie Tucker. Gurock says that Al Jolson “hung out in Harlem” although he never actually lived there.

Baseball player and World War II spy Moe Berg, who was born in Harlem, may qualify; a film about his life is currently in production with Paul Rudd in the starring role.