Vatsyayana 
The Karma Sutra [EPUB ebook] 

The Kama Sutra, is an ancient Indian text widely considered to be the standard work on human sexual behavior in Sanskrit literature written by the Indian scholar Vatsyayana. A portion of the work consists of practical advice on sex. Kāma means sensual or sexual pleasure, and sūtra are the guidlines of yoga, the word itself means thread in Sanskrit.
The Kama Sutra is the oldest and most notable of a group of texts known generically as Kama Shastra). Traditionally, the first transmission of Kama Shastra or 'Discipline of Kama’ is attributed to Nandi the sacred bull, Shiva’s doorkeeper, who was moved to sacred utterance by overhearing the lovemaking of the god and his wife Parvati and later recorded his utterances for the benefit of mankind.