The Kama Sutra, also known as the Kama Sutra of Vatsyayana, is an ancient Indian Sanskrit text on human sexual behavior and life. It is attributed to the author Vatsyayana Mallanaga, who is believed to have lived in the 2nd century CE.
If you are looking for the most complete academic version, the hosts various full English translations, such as The Kama Sutra of Vatsyayana kaama sutra sinhala pdf