By 1980, the global smallpox vaccination campaign had resulted in the complete eradication of the deadly disease. Ward’s captivating and informative book relates events that took place two centuries earlier and laid the foundation of this unique achievement. In 1768, the Russian Empress Catherine the Great invited the English doctor Thomas Dimsdale to Russia to inoculate her and her teenage son, the heir to the throne. Catherine was the first monarch to be inoculated against smallpox, at a time when none of her European peers were willing to take the risk. (Smallpox killed five reigning European rulers in the eighteenth century.) Both Catherine and her doctor were ardent proponents of the Enlightenment; both believed in science and valued persuasion over coercion; and both worked tirelessly to overcome people’s prejudices and superstitions. Catherine used the power of her own example to encourage inoculation across her empire. The doctor, inspired by a vision of the wholesale eradication of smallpox, published treatises to popularize his methods and campaigned to extend smallpox inoculation to the poor. Catherine granted him the hereditary title of baron and showered him with gifts. They remained friends even after he returned to England. In 1781, Catherine brought him back to Russia to inoculate her two young grandsons.