At first glance, Bob Damron’s Address Book reads like any other travel guide. Bars, restaurants, hotels and businesses are grouped by city and state, their names and addresses listed in alphabetical order. An introductory note reassures readers that the information contained within the volume is up-to-date, while classifications written in abbreviated parentheticals offer travelers additional details on specific establishments: An asterisk, for example, indicates a place is “very popular,” while the letter “D” specifies if a bar or club has space for dancing.

Ostensibly universal, Damron’s handbook, first published in 1964 and still released annually, was actually directed toward a specific—and secretive—audience. As Eric Gonzaba, a historian at California State University, Fullerton, explains, Damron, a white, gay man from San Francisco, “started just writing down lists of locations that he would visit, … places [where] he either found other gay men or he felt accepted.”

What began as a personal reference for the Californian and his friends soon morphed into a thriving enterprise akin to The Negro Motorist Green Book, which safely shepherded African American travelers across the country during the Jim Crow era, but for gay men and, to a lesser extent, lesbian women. Crucially, Damron’s Address Book never explicitly identified its target audience (at least until 1999, when the word “gay” was first printed on its cover), instead relying on euphemisms, innuendo and coded abbreviations to circulate information within the queer community.

A new public history initiative spearheaded by Gonzaba and Amanda Regan, a historian at Southern Methodist University, is poised to bring Damron’s findings into the digital age, drawing on more than 30,000 listings compiled between 1965 and 1980 to visualize queer spaces’ evolution over time. Titled Mapping the Gay Guides, the project aims to “correct the cultural erasure of historical geography” by spotlighting local communities’ oft-unheralded queer history and, adds Gonzaba, exploring “how that community relates to other parts of the country.”