The most valuable and also vexing thing about nightclubs is that you can’t get in. Not to the good ones, at least. Not unless you are in the know, or in good standing with people who are, or are diligent and passionate and perhaps willing to part with a bit of cash. Nightclubs are not for public consumption — there is a clear demarcation line of knowledge and access, and the mythology of a great club is built as much by the curious kept on the outside as the revelers doing damage on the inside.

This is perhaps less true today, in an age when nightclub culture is heavily monitored and policed, or maybe worse, heavily commodified. But in the New York of the 1980s and 1990s, clubs were somehow both utopian and forbidding. They were a world where all the most relevant synergy was taking place, and yet to almost everyone they were a wholly inaccessible secret.

Image Clockwise from left: MC Delite, Kool DJ Red Alert, Grandmaster Melle Mel and DJ Jazzy Joyce, from “No Half Steppin’.” Credit... The Paradise Gray Collection/No Half Steppin'

That particular tightrope walk is captured in a pair of new books, but in opposite ways. “No Sleep: NYC Nightlife Flyers 1988-1999” (powerHouse) by Adrian Bartos (a.k.a. D.J. Stretch Armstrong) and Evan Auerbach, a hip-hop archivist, is a collection of party fliers from several waves of the city’s after-hours life, from hip-hop to house to Latin music and beyond. They are advertisements, enticements and also obscure code, meant to be discerned by only a select few. “No Half Steppin’: An Oral and Pictorial History of New York City Club the Latin Quarter and the Birth of Hip-Hop’s Golden Era” (Wax Poetics), by Claude Gray, a.k.a Paradise, and Giuseppe Pipitone, a.k.a. u.net works from the inside out, telling some of the history generated at one of the city’s foundational hip-hop clubs.