When 22 year old aspiring geologist Charles Darwin boarded HMS Beagle in 1831, he hardly thought he was embarking on what would become perhaps the most important voyage in scientific history. Nonetheless, over the course of the hazardous five-year journey, Darwin would make observations and gather samples that would form the basis of his revolutionary theories about the origin of species and natural selection. Chronicling the voyage as it unfolded, Diana Preston details how the experience shaped Darwin's life, his mind, and his remarkable idea.