This study portrays a man and an age. Yom-Tov Lipmann Heller (1578-1654), author of the famous Mishnah commentary Tosafot yom tov, was a major talmudist, a disciple of the legendary Rabbi Judah Loew of Prague, and himself the distinguished chief rabbi of Prague and Cracow. The time in which he lived began as a 'golden age' for the Jews of Prague and the Jews of Poland, an age of prosperity and the rise of Jewish mysticism. During Heller's lifetime, however, the golden age changed to darkness, and prosperity gave way to war, persecution, plague, and massacres. It was the end of the Middle Ages, the last generation before Spinoza and Shabbetai Zevi. Scholar, preacher, religious and communal leader, Heller embodied a religious and cultural ideal; he was the very model of a seventeenth-century rabbi. Born in Germany, he moved from one end of the world of Ashkenazi Jewry to the other, first to Prague, and then to Poland and the Ukraine. His life was enmeshed in a web of family ties, and bou