Charles Darwin's curiosity had a remarkable childlike enthusiasm driven by an almost compulsive appetite for a constant process of discovery, which he never satiated despite his many voyages. He would puzzle about the smallest things, from the wonders of barnacles to the different shapes, colours and textures of the beetles which he obsessively collected, from flowers and stems to birds, music and language, and would dedicate years to understanding the potential significance of everything he saw. Darwin's findings and theories relied heavily on that same curiosity, on seeking and answering...