Cotton Mather was one of the most influential religious leaders in early America. He assumed responsibility for sustaining the reforming zeal of the Puritan movement begun by his ancestors, who left England to establish an idealised society in New England. As the seventeenth century drew to a close, the Calvinistic principles on which the early communities had been based were no longer adhered to quite so strictly, and Mather saw it as his religious duty to revitalise Puritanism and stop the degeneracy that he saw all around him. His Magnalia Christi Americana was an enormously ambitious work with which Mather hoped to demonstrate to the world God''s support for the Puritan cause in New England, and thus rekindle the Reformation throughout Europe and the rest of the civilised world. One of the issues this study will consider is to what extent Cotton Mather achieved his purpose. It will consider in detail the language he used to express his beliefs and, like him, taking the Bible as a guide, try to assess the value of his achievement. His accuracy as a historian will also be considered and an attempt will be made to understand the relevance of his work to a modern audience.