No one seems to have ever fully rifled through its contents, save for a researcher here and there, said Whit Waterbury, an archivist and librarian at the Neighborhood Playhouse, the conservatory where Robert Duvall, Jeff Goldblum and Allison Janney trained.

So several years ago, Waterbury rolled up his sleeves and got busy.

Most of the materials he found had to do with the early days of the theater, between 1915 and 1927. Photographs and playbills of a Hindu drama attributed to King Shudraka in 1924. Productions featuring the music of Ernest Bloch, Claude Debussy and Alexander Borodin.

And then he found the book.

At first, he didn’t think much of the dusty thing, with its fragile binding and fading yellow ribbon on the outside. He set it aside to focus on documents more clearly related to the school and its founders, Alice and Irene Lewisohn, two sisters and community activists who built one of the first off-Broadway theaters in New York.

But then last spring, he actually flipped through its pages. There was Eleanor Roosevelt’s signature. And Amelia Earhart’s. The journalist Jacob Riis wrote a nice note. So did New York’s four-time governor Alfred E. Smith.

This was not simply a Neighborhood Playhouse artifact. Rather, it represented a much broader yet little-known chapter of New York history, centered around a nurse-turned-social reformer named Lillian Wald, who set a national example of how to help and empower the working poor. The book was proof of this.

Waterbury wrote an email to the leadership of the Henry Street Settlement, a social service, arts and health care organization on the Lower East Side, which Wald founded 126 years ago.

He rattled off the names of the famous signatories, explaining that at some point, the book must have gotten bundled with other papers when the theater left its original home on the Lower East Side.

“I’ve gone through it and it’s clearly from Henry Street: most of the inscriptions refer to Ms. Wald and the settlement work,” he wrote.

“The trunk was something out of Narnia,” said Barbara Kancelbaum, vice president of marketing and communications for the Henry Street Settlement. She immediately arranged to meet him and collect it. It’s been sitting in an archival box in her office ever since.

The newly recovered guest book, it turns out, underscores how everyone who was anyone in politics or the social-reform movement of the early 20th century wanted to meet Wald, Kancelbaum said.

For example, Sidney Hillman, a prominent labor leader, wrote in the book in 1934 that he hoped the New Deal would be as successful as Wald’s work with Henry Street.

Settlement houses, which began in London in the 1880s in response to the rampant poverty brought on by the industrial revolution, are community-oriented social service agencies. There are still 42 of these organizations across New York.

The idea behind the settlement movement was that if you wanted to help a community, you needed to live among its residents.

Henry Street, created in response to a growing immigrant population living in squalid conditions, was one of New York’s first settlement houses. It was partly inspired by Chicago’s Hull House, which was started by the activist Jane Addams, who also signed Wald’s guest book.

Wald certainly helped the Henry Street community, if not the entire city.

A fierce advocate for children, she created the first playground in New York City; pioneered special education; introduced the concept of free lunches and nurses in schools; and fought against child labor.

In 1893, Wald, who came from a wealthy family in Rochester, had an experience that would change her life forever. She was helping a friend by teaching a home economics class for immigrants on the Lower East Side.

Suddenly, a girl rushed in and told Wald that her mother was bleeding to death in childbirth and that the doctor had abandoned the family because they couldn’t afford to pay him. Wald, a trained nurse, left immediately to help. She saved the woman’s life.

Soon thereafter, she relocated to the Lower East Side, founding the Henry Street Settlement that same year. In 1895, Jacob Schiff, a prominent banker and Wald’s lifelong friend and benefactor, bought a large house on Henry Street to serve as the settlement house's headquarters.

Wald originally focused on providing health care for immigrants. She hired between 80 and 90 nurses, around 10 of whom would live with her on Henry Street.

Out of this effort, the Visiting Nurse Service of New York was formed. It 1944, it became its own organization. It is still thriving today. So is Henry Street, which serves over 50,000 people a year. It runs 18 locations throughout the Lower East Side, including four homeless shelters, providing services from after-school programs to job training.

Known as a social reformer, Wald also felt strongly that the arts should play an integral part in the settlement house’s programming, Kancelbaum said.

This is where Irene and Alice Lewisohn, the theatrical sisters and philanthropists, came in. In 1915, after directing some drama clubs at Henry Street, the Lewisohns built the Neighborhood Playhouse on Grand Street (the building is still there).

But in 1927, they stopped producing theater on Grand Street, deciding to start an acting conservatory instead. In 1947, they bought two adjoining buildings on East 54th Street and moved in.

So, apparently, did Wald’s guest book.

Last year, for its 125th anniversary, Henry Street Settlement introduced a permanent exhibition, which covers the history of the organization, and of the neighborhood it serves, at its headquarters.

Officials there have plans to digitize the book and incorporate it into the exhibition.

“Henry Street was known as a hotbed of fomenting solutions to the problems of the time,” so all kinds of political and cultural leaders would visit, Kancelbaum said.

Throughout the 20th century, the settlement house served as a destination for civil rights leaders like W.E.B. DuBois, who visited Henry Street’s stately dining room for the reception celebrating the NAACP’s founding conference. Decades later, Rosa Parks stayed there while attending a rally at Madison Square Garden, just five months after her arrest.

“Our doors are still wide open,” said David Garza, the president and chief executive of Henry Street. “Neighbor helping neighbor is a critical component and defining characteristic of what it means to be a settlement.”

For those who do stop by, there is even a new guest book to sign.

This article originally appeared in The New York Times.