Some of us are old enough to remember lining up at school for polio vaccine. It's hard to convey what it meant to our parents to know this childhood terror could be prevented with a simple oral dose of medicine (bless you, Dr. Salk).In the 17th & 18th C., smallpox destroyed populations, upset the balance of power in European courts as it killed rulers and heirs, and terrified communities at the first sign of the distinctive pox. Prior to Edward Jenner making the connection between cowpox and smallpox vaccination, two brave individuals, a Boston physician named Zabdiel Boylston and an English aristocrat, Lady Mary Wortley Montagu, risked ridicule, censure and even death threats to spread the idea of inoculation against smallpox. They didn't fully understand the disease, but they did see how people in Turkey, and African slaves, exposed themselves to the disease through subcutaneous methods and gained immunity. To save their children, Boylston and Lady Mary risked all and inoculated them against "the speckled monster".If you like medical histories, you'll enjoy this book. The author writes in an easy, novelistic style that brings the characters to life and makes it read like a mystery. The research is wonderful, but be forewarned--it contains photos of smallpox victims in the terminal stages of the illness that are not for the faint of heart.Smallpox ceased to be a threat in the 1970s. Other diseases have cropped up to concern us, but none of them have the impact of what smallpox did in its time.