Emily Warren Roebling was not an engineer. But she was a woman of “strong character” with an “almost masculine intellect,” as the biographer Hamilton Schuyler once described her, who was instrumental to one of the greatest architectural feats of the 19th century. Connecting Brooklyn and Manhattan for the first time, the Brooklyn Bridge was the world’s longest suspension bridge at the time. Fourteen years in the making, its construction was complicated by corrupt politicians and crooked contractors. Upon completion, it was immediately proclaimed the “Eighth Wonder of the World.”

“I don’t think that the Brooklyn Bridge would be standing were it not for her,” said Erica Wagner, the author of “Chief Engineer: Washington Roebling, the Man Who Built the Brooklyn Bridge,” a biography of Emily Roebling’s husband. “She was absolutely integral to its construction.”

Emily Warren was born in 1843 in Cold Spring, N.Y., one of 12 children of Sylvanus Warren, a New York State assemblyman, and his wife, Phebe Lickley Warren. In her teens, she traveled to Washington to attend the prestigious Georgetown Academy of the Visitation, where she studied history, astronomy, French and algebra, among other subjects — in addition to housekeeping and needlework. “Her intelligence, liveliness and charm were always apparent to those around her,” Wagner writes in “Chief Engineer.”

She met her husband, the civil engineer Washington A. Roebling, through her brother, G.K. Warren, a general in the Civil War under whom he served. The son of John A. Roebling, a German-American engineer known for building suspension bridges (and for his short temper), the younger Roebling was struck by Warren right away, Wagner said. After they were married, he would describe his wife as “a woman of infinite tact and wisest counsel.”

The Roeblings married in 1865 and soon set off for Europe, where a pregnant Emily would accompany her husband in the study of caissons, the watertight structures filled with compressed air that would later enable workers to dig beneath the East River. Back home, the elder Mr. Roebling was preparing for construction of a suspension bridge across the East River that he boasted would be “the greatest bridge in existence.” In those early days, it was called the “Great East River Bridge.”

The Brooklyn Bridge would go on to become, at least according to lore, the most photographed structure in the world; a gateway to that “shining city,” as Thomas Wolfe once described it, whose granite towers and thick steel cables have inspired countless artists, musicians, engineers and architects.

But its construction was far more treacherous than most casual pedestrians know.

Just a few days in, while surveying the construction site, the elder Mr. Roebling had his foot crushed in the pilings of a Brooklyn pier when a barge came in to dock; he contracted tetanus and died less than a month later. His son succeeded him as chief engineer — only to later become incapacitated by a mysterious illness that left him partially paralyzed, blind, deaf and mute, according to reports at the time. (It was later believed that Mr. Roebling suffered from “caisson disease,” or the bends, a kind of decompression sickness caused by changing air pressure not uncommon on bridge-building sites.) At least two dozen other men died working on the bridge, according to David McCullough’s “The Great Bridge.”

“It was a struggle physically, it was a struggle politically, it was a struggle financially,” said Richard Haw, the author of “The Brooklyn Bridge: A Cultural History” and a coming biography of John Roebling. “The bridge was built by hand, so there were a lot of lost fingers. There were falls, and no safety net to catch you. There was a huge amount of undocumented injuries.”

Enter Emily Warren Roebling. A woman who, in later life, would study law at New York University and argue in an Albany law journal article for equality in marriage. She became her husband’s “eyes and ears,” Haw said.

She began as secretary, taking copious notes. She went back and forth to the construction site. She negotiated the supply materials, oversaw the contracts, and acted as liaison to the board of trustees. Eventually, she became a kind of “surrogate chief engineer,” according to a biography of Warren by the historian Marilyn Weigold, a professor at Pace University. She used her “superb diplomatic skills” to manage competing parties — including the mayor of Brooklyn, who tried to have her husband ousted from the project.

During the final years of the bridge’s construction, her husband looked out from his bedside window in Brooklyn Heights — using a telescope and binoculars to watch the bridge grow.

“All along, he is present,” Wagner said. “But he is not able to go to the bridge, and he’s not able to see anyone. But amazingly, he holds this extraordinary structure in his head. And she is able to help him transmit his thoughts.”

As Emily Roebling put it, years later, in an 1898 letter to her son: “I have more brains, common sense and know-how generally than have any two engineers, civil or uncivil, and but for me the Brooklyn Bridge would never have had the name Roebling in any way connected with it!”

The bridge finally opened on May 24, 1883, to great fanfare. On that day, thousands crossed, under a sea of fireworks, with The Times declaring that “no one man can be given the credit of this colossal undertaking.” In another article, The Times reported “How the Wife of the Brooklyn Bridge Engineer Has Assisted Her Husband.”

Today, there is a plaque on the bridge honoring all three Roeblings. It reads: “Back of every great work we can find the self-sacrificing devotion of a woman.”

Emily Roebling died on Feb. 28, 1903, in the Roebling’s Trenton home, of stomach cancer.