For generations, Kabbalists and mystics attributed special significance to studying the Torah at night, in particular. This kind of study has a unique ability to bring about ‘tikkun’ (remedy) against calamities liable to befall the Jewish people or the world at large. This is all the more so for the Shavuot holiday, festival of the giving of our Torah. In the Book of the Zohar, the fundamental book of the Kabbalah, is says that the ancients did not sleep the night of Shavuot; rather, they engaged all night long in study of Torah. The custom became widespread among the Kabbalists of Safed (Tzfat) during the 16th century, and still exists to this day. In some ethnic groups, men engage the whole night in the ‘Service of the Night of Shavuot’ – an abstract of all the books of the Old Testament (Tanach), the Mishnah, the Talmud and the Zohar.