For a British Empire that stretched across much of the globe at the start of the nineteenth century, the interiors of Africa and Australia remained intriguing mysteries. The challenge of opening these continents to imperial influence fell to a proto-professional coterie of determined explorers. They sought knowledge, adventure, and fame, but often experienced confusion, fear, and failure. The Last Blank Spaces follows the arc of these explorations, from idea to practice, from intention to outcome, from myth to reality. Those who conducted the hundreds of expeditions that probed Africa and Australia in the nineteenth century adopted a mode of scientific investigation that had been developed by previous generations of seaborne explorers. They likened the two continents to oceans, empty spaces that could be made truly knowable only by mapping, measuring, observing, and preserving. They found, however, that their survival and success depended less on this system of universal knowledge