BDSMBooks
From wipipedia.org

BDSMBooks publishes books, e-books and e-videos (films available on-line or downloadable). It was founded in 1999 by Pentland Hick, who previously owned another BDSM-related publishing house Silver Moon Books.
BDSMBooks publishes several e-books monthly on themes of erotic domination, ranging from mild to hard. Their website allows book searches based on their own 'Strength' rating. They have several authors, most of whom also use other publishers.