Where Willy Went is a British children's picture book written and illustrated by Nicholas Allan.

The book is about a sperm named Willy who lives inside Mr Browne.

Just like other 300 million sperms, Willy races trying to catch the prize, an egg.

[2] This book is written in an innocent, warm, accessible language and can be easily read by young children.

It is also a useful guide for parents in need of simple explanations for facts of life.