Dr Tatiana's Sex Advice to All Creation: The Definitive Guide to the Evolutionary Biology of Sex is a 2002 popular science book by the British evolutionary biologist Olivia Judson written in the role of her alter ego, agony aunt Dr Tatiana.
Dr Tatiana receives letters from various creatures about their sex lives, and responds by explaining the often surreal biology of sex to creatures concerned. Of course this is merely a humorous vehicle with which Judson communicates with the human reader.
The books grew out of the article "Sex Is War!" she had written for the Economist in 1997. The book was shortlisted for the 2003 Samuel Johnson Prize. It was later turned into a musical of the same name, shown on Channel 4 in 2005.