The Holy Letter: A Study in Jewish Sexual Morality is a translation of Iggeret ha-Kodesh, a thirteenth-century Hebrew text whose authorship, while unknown, is traditionally attributed to Nahmanides. On one level, The Holy Letter is a sexual treatise, a guide for the marital relationship. On an esoteric level, it is a kabbalistic work depicting God's relationship to his people. The relationship between a husband and wife is sacred in Judaism. An important aspect of that relationship is the sexual union. Lovemaking between husband and wife is a holy act, a mitzvah, especially on the Sabbath. Jewish tradition considers sexual intimacy to be above and beyond the commandment to "be fruitful and multiply". Even a barren couple is commanded to make love, for it is a spiritual union that brings husband and wife closer to each other and closer to God. Within The Holy Letter we find the prohibition against a husband having intercourse with his wife against her will. We see that, in Jewish tradition, husband and wife are partners: "The union of man with his wife, when it is proper, is the mystery of the foundation of the world and its civilization. Through the act they become partners with God in the act of creation. This is the mystery of what the sages said, 'When a man unites with his wife in holiness, the Shekhinah is between them in the mystery of man and woman.'" While it is a mitzvah for the husband to give physical pleasure to his wife, the holiness of the act must never be forsaken. "The mystery of man includes in his being the mystery of wisdom, understanding, and knowledge. Know that the man is the mystery of wisdom and the female is the mystery of understanding. And the pure sex act isthe mystery of knowledge. Such is the mystery of man and woman in the esoteric tradition. If so, it follows that proper sexual union can be a means of spiritual elevation when it is properly practiced, and the mystery great