"This is the global history of early vaccination. In the late eighteenth century, Jenner demonstrated that inoculating cowpox could be an effective and viable means of preventing smallpox and, by using humanised cowpox (vaccine) drawn from children subject to the procedure, hit on the means to make the disease sustainably and universally available. The book provides the first comprehensive account of the spread of vaccination through networks of global connection during the Napoleonic Wars. It is about the parents who gave cowpox a chance, the medical networks that put several million children around the world arm-to-arm, the successes and failures of early vaccination, and the measures that made mass immunisation feasible. It is the history of a remarkable mobilisation that transformed many lives, a revolution that was an emancipatory force, even as it came to represent the pointy end of growing state power, and the foundation of later advances in preventive medicine. By the coming of peace in 1815, the war against smallpox had begun to bring smallpox's empire within bounds"--.