Joseph Papp had a simple idea that the greatest writer in the English language belongs to the people, said the Public Theater’s new artistic director Oskar Eustis. He was speaking at New York Public Library for the Performing Arts, at the opening of an exhibit celebrating 50 years of theatrical innovation at the Public Theater. Mr. Eustis welcomed a crowd who viewed archival photographs, scripts, interviews, videos, films, set designs, and posters. Running through October 15, the exhibition – like Papp’s dream for Shakespeare in the Park – is free.

In an American style with nontraditional casting, the visionary Papp staged productions that allowed audiences to encounter Shakespeare and the classics afresh. His vision grew from its hardscrabble start in 1954 on the Lower East Side, through interborough travels on mobile stages, and finally to the Delacorte Theater in Central Park and the Public Theater itself, which opened downtown in 1967 in the former Astor Library.

The exhibition lives up to its title, “A Community of Artists” – from the entranceway scrim depicting James Earl Jones and Kathleen Widdoes in “A Midsummer Night’s Dream” to the 25-foot wall onto which a rolling display of 6,700 names of artists are projected, season by season, including Kevin Spacey, Jerry Stiller, Val Kilmer, and the magician Ricky Jay.

At the exhibit, a former artistic director of the Public Theater, George Wolfe, told the Knickerbocker how strange it was to see theater “which always exists in the mess” in a museum setting: now “all of a sudden it’s organized.”

Visitors can see Edward Kleban’s notes and revisions of lyrics from “A Chorus Line,” which opened in 1975, as well as souvenirs from the 2,289th and 5,000th performance of the spectacularly successful show. There are also crowns and exotic headgear from Shakespeare productions; posters from the Aquarian-age sensation “Hair” and David Rabe’s Vietnam-era “Streamers”; examples of Ming Cho Lee’s seminal set designs; and much else.

Echoes of master builder Robert Moses appear in the first display case, which contains this rebuff of a request by stage doyenne Helen Hayes in 1958: “I have your letter of June 12. Frankly I don’t care to take a leading part in further celebrating and advertising Mr. Papp.” There’s also a missive Papp wrote to Moses, “I am starting a campaign to raise funds for next summer’s productions in the park.” The commissioner wrote dismissively: “won’t work.” Papp prevailed against Moses’s complaint that a theater would hurt the lawns in Central Park: Theater lovers sent Moses grass seed by mail.

Gail Merrifield Papp, secretary of the Public Theater Board of Trustees and widow of Joseph Papp, recalled the inconvenience of climbing warehouse ladders, prior to the deposit of Joseph Papp’s personal papers and the New York Shakespeare Festival Records as the largest archival collection at the New York Public Library for the Performing Arts. She said Papp introduced multicultural casting when it was still considered a radical concept. American Theatre editor Jim O’Quinn likewise told the Knickerbocker that the goal of an inclusive American theater was crucial to understanding Papp’s legacy.

At a press conference Monday, Mr. Eustis introduced actor Liev Schreiber, saying he “is really too young to be in a museum yet.” Mr. Schreiber recalled Mr. Wolfe asking him to play a small role in “The Tempest.” He paused. “I held the spear well.” Kevin Kline also recalled carrying a spear in “Wars of the Roses” during the Papp era.

Attending the exhibition were Marymount Manhattan College theater professor Bill Bordeaux, who had a student in “Bring in ‘da Noise, Bring in ‘da Funk”; actress Valda Setterfield; Georgia Delano,a supporter of the Public Theater; Alec Baldwin, who called Papp “ferociously bright”; F. Murray Abraham; and photographers Martha Swope and Ray Fisher.

The latter recalled a dinner party in the Berkshires in the late 1980s. Having heard of Papp’s prodigious memory, Mr. Fisher inquired about his Bar Mitzvah speech. Papp proceeded to recite it.

The night’s attendees were a veritable chorus line of Public Theater figures, including Roger Gindi, company manager for the “Runaways” in 1977-8; Estelle Parsons, who is reviving “Miss Margarida’s Way”; and Alison Harper, who worked at the New York Shakespeare Festival from 1967 to 2003 in various roles. She said her favorite “Hamlet” production featured Stacy Keach, Colleen Dewhurst, and James Earl Jones.

Publicist Richard Kornberg recalled the time a Brazilian Shakespeare Company was coming to perform a Portuguese production of “A Midsummer Night’s Dream.” He was at a loss as to how to promote it, until he learned that the female sprites would be topless. He asked Papp about publicizing the show as “the first nude Shakespeare.” Papp thought no one would care. He was wrong: At the open rehearsal alone, 14 television crews arrived, undaunted by the rain.

Steven Cohen, a former Public Theater producing director, said that when “Hair” was being made, its creators heard the line “what a piece of work is man” in a production of “Hamlet” downstairs, and were inspired to write a song for “Hair” with that title. Actual hair also brought bad luck on one occasion. Mr. O’Quinn recalled during Tina Howe’s play “The Art of Dining,” actress Dianne Wiest’s hair caught on fire and she ran offstage.

The Knickerbocker asked playwright and activist Larry Kramer to comment on the show. With a mischievous grin, he led the Knickerbocker toward the front of the gallery and wrote an asterisk and “Larry Kramer” alongside names of artists Ntozake Shange, David Rabe, Miguel Pinero, Adrienne Kennedy, David Mamet, Suzan-Lori Parks, David Huang, and others that had been neatly typed. Below he wrote of himself: “whose play ‘The Normal Heart’ remains the longest running play in the history of the Public Theater.”

Mr. Eustis said that amended poster could be auctioned at a fund-raiser. Another person was overheard to say that live performance was not easy to capture at an exhibition, and this proved an example. Curator Barbara Cohen-Stratyner was later seen showing Mr. Kramer a display case at the other end devoted to his play along with protest buttons such as “Silence = Death.”