High Quality Content by WIKIPEDIA articles! Robert Calef (ca. 1648-1719 Roxbury, Massachusetts) was a Boston, Massachusetts Baptist cloth merchant who came to America before 1688. He is best known as the author of More Wonders of the Invisible World, a treatise that he published in 1700 against the state clergy, particularly Rev. Cotton Mather, for its role in the Salem witch trials. Because no Boston publisher would accept the book, it was printed in England. Rev. Increase Mather, father of Cotton, publicly burned the book in Harvard Yard.