This is the first biography of Sir Simonds D'Ewes, an English country gentleman, lawyer, Puritan, historian and antiquarian who lived from 1602-1650. He left the most extensive archive of personal papers of any individual in early modern Europe, and this is the first thorough exploration of it. Biographies of his contemporaries usually emphasize either their public or private lives, but not both, because of the limitations of the sources. For D'Ewes, both are richly available and provide the basis for the most detailed description of an individual's life from childhood until death that can be written. His relationships with his two young wives and their children and his parents, siblings, friends and enemies are vividly portrayed. His life and thought before the Long Parliament to which he was elected in 1640 are carefully analyzed, so that the mind of one of the Parliamentarian opponents of King Charles I's policies can be understood more fully than that of any other MP. Although conservative in social and political terms, D'Ewes's Puritanism prevented him from joining his Royalist younger brother Richard during the civil war that began in 1642. In the late 1630s, he seriously considered emigration to Massachusetts. He collected one of the largest private libraries of books and manuscripts in England in his era and used them to pursue historical and antiquarian researches. He followed news of national and international events voraciously and conveyed his opinions of them in to his friends in many hundreds of letters.