Over the next six weeks Greencine will be serializing Eddie Muller’s 1996 non-fiction book Grindhouse: The Forbidden World of “Adults Only” Cinema.

Grindhouse: The Forbidden World of “Adults Only” Cinema (1996) – Eddie Muller
[Amazon.com] [FR] [DE] [UK]

From the beginning of the book:

Grindhouses have always churned away in a seamy corner of the American psyche. They glowed through the fog on the bad stretch of Market Street in San Francisco. They used dizzying neon to bewitch New Yorkers, even in the bustling depravity of Times Square. From First Avenue in Seattle to Canal Street in New Orleans, if you wanted to see all the sexy stuff that the Purity Patrol kept from the mainstream, a grindhouse always beckoned.

The best online definition of the grindhouse genre is by Brian Camp:

Grindhouse was a term coined and perpetuated by the trade paper, Variety, to describe theaters on big-city downtown movie strips, like New York’s 42nd Street or San Francisco’s Market Street, which ran double (and sometimes triple) features of films continuously, practically around the clock, with little or no time between films (i.e., the films ‘grinded’ up against each other). Such theaters don’t exist anymore. When we talk about ‘grindhouse movies,’ we refer to the types of action and exploitation movies that played at these theaters (blaxploitation, Italian westerns, kung fu, slasher, etc.).” –Brian Camp , 09/28/2003, 08:56:54 via http://www.mhvf.net/forum/general/posts/124245630.html 

See also:

exploitation film – grindhouse cinema – sex film – sexploitation