One of THE books on New York "alternative" art

Ault's book was my introduction, along with an amazing seminar taught by Robert Storr, to alternative "spaces, places and voices" in New York between the 1960s and 1980s. (For those interested in further details, it was an expanded (somewhat way) after-the-fact catalogue for a 1996 exhibition at The Drawing Center. The book was published in 2002.) If you have any interest in the subject this is the place to start. 
Find it here.