Yom Kippur, also known in English as the Day of Atonement, is the most solemn and important of the Jewish holidays. Its central themes are atonement and repentance. Jewish people have traditionally observed this holiday with a 24-hour period of fasting and intensive prayer. Total abstention from food and drink usually begins 30 minutes before sundown and ends after nightfall the following day. Although the fast is required for all healthy adults, it is waived in the case of certain medical conditions. Virtually all Jewish holidays involve a ritual feast, but since Yom Kippur involves...