Velvet Underground is a book that was punblished by Michael Leigh in 1963. The book contained information on any non-vanilla sexual practice.
That is to say anything that is not the traditional male/female lovemaking. It included subjects of homosexuality, S&M,group sex-you name it.

It is said to have started a sexual revolution. I once saw this book in a S&M bookstore when I was visiting Toronto a while back and regret not
buying it. Anyway in the UK the book's title changed to Bizarre Sex Underground (see pic, courstesy of the trashfiction website).

The book's original title was the inspiration for naming the 1960's band Velvet Underground (Lou Reed's first band). Their Venus in Furs song,
inspired by a novel by Leopold Sacher Von-Masoch, is one of the best S&M song in my humble opinion. If you could think of a better one, or even
any one, feel free to lcomment and let me know! Here's a clip of the song.