The story of one tiny creature and history's most spectacular scientific breakthrough.

In 1846, Charles Darwin has a secret: an essay, sealed in an envelope and locked in his study drawer, which will overturn human understanding of time and nature forever. Now he must publish and take the consequences. But he hesitates.

First, Darwin decides to undertake just one small task: to solve the riddle of a tiny barnacle he picked up on the shores of Southern Chile, the last of his Beagle specimens. As it turns out, he could not have made a more fateful choice.

Barnacles are common to almost every shoreline in the world, but this barnacle doesn't fit established definitions or accepted archetypes. He promises himself a month or so studying this creature, this potential key, to try to understand the process of natural selection within this particular species. But eight years later, his study filled with hundreds of barnacle specimens in labelled pill-boxes posted from around the world, the case is still unclosed.

Was Darwin hesitating? Or was he testing his 'dangerous idea' to destruction? Lavishly illustrated and superbly told, Darwin and the Barnacle is the fascinating story of how genius sometimes proceeds through indirection - and how one small item of curiosity contributed to history's most spectacular scientific breakthrough.