In her Introduction to The Eighteenth-Century Commonwealthman, Caroline Robbins wrote that the Commonwealthmen were "a gifted and active minority of the population of the British Isles, who kept alive, during an age of extraordinary complacency and legislative inactivity, a demand for increased liberty of conscience.". Their essays, arguments, pamphlets, and histories -- a continual flow from the late seventeenth century to the end of the eighteenth -- were hugely popular in America. The themes presented were revolutionary: separation of powers, natural rights, rotation in office, religious freedom, a supreme court, and resistance to tyranny. They achieved very little political success, but the documents of later generations are full of ideas kept alive by the Commonwealthmen in difficult times. In The Eighteenth-Century Commonwealthman, Robbins adeptly presents a history of these men, whose writings advocated the principles of liberty in an era when change was considered perilous.