Joachim Jungius, of Lübeck, represents the German counterpart to Galileo Galilei in Italy, René Descartes in France, and Francis Bacon in England as an innovator in science and philosophy. Unlike these men, Jungius did not achieve an international reputation; even among scholars, interest in him has been largely confined to Germans, whose curiosity has been whetted by Gottfried Wilhelm Leibniz's enthusiastic praise of his merits as a philosopher. But Jungius exercised a wide personal influence in Germany as an active teacher. Furthermore, like Bacon, he envisaged a scientific society that would promote the welfare of humankind: Jungius actually organized a group called the Societas Ereunetica, whose stated objective was to promote sound science and combat false opinions. This group, with its stress on mathematics and logic as an antidote to metaphysical and mystical speculation, invites comparison with the Vienna circle of the twentieth...