Actors' Equity Association (AEA) is the union of professional legitimate stage actors and stage managers. It was founded in New York City in May 1913, but did not gain full recognition as the bargaining agent for actors until the historic strike of 1919.

AEA negotiates contracts and agreements that often affect a productions theatre program. Over the years rules regarding billing, program biographies, and Equity recognition in programs have become part of these contracts and agreements.

The bulk of the programs in this collection came from Paul Ross. An Equity stage manager, Ross was the publisher of the Players' Guide, a compilation of actors' photographs and credits arranged by sex and type. He collected these programs from Equity representatives who attended shows as well as from his own participation. He used them primarily to check credits for inclusion in the guide.

The staff of Actors' Equity also uses programs to determine if all contractual obligations have been fulfilled and if a member is under the correct contract (principal or chorus). Some of the programs in the collection, most often from the 1930s, include notes but it is unclear under what circumstances these notes occurred since Equity would usually put a program with notes in an individual production file.

Demonstrating the enormity and diversity of theatre in America during the 20th Century, the collection gives more than just a list of players in a given production. The programs offer a look into how productions were presented, how advertising changed over the years, and how some productions continue to be produced generation after generation.