In Christianity and Judaism, the Book of Life (Hebrew: ספר החיים, transliterated Sefer HaChaim) is the book in which God records the names of every person who is destined for Heaven. According to the Talmud it is open on Rosh Hashanah; its analog for the wicked, the Book of the Dead, is open on this date as well. For this reason extra mention is made for the Book of Life during Amidah recitations during the Days of Awe, the ten days between Rosh Hashanah, the Jewish new year, and Yom Kippur, the day of atonement (the two High Holidays, particularly in the prayer Unetaneh Tokef).

In the Old Testament, the Book of Life is the book or muster-roll of God, in which all the people who are considered righteous before God are recorded forever. God has such a book, and to be blotted out of it, signifies death. It is with reference to the Book of Life that the holy remnant is spoken of as being written unto life; in Jerusalem compare also Ezekiel ix. 4, where one of the six heavenly envoys "who had the scribe's inkhorn upon his loins" is told to mark the righteous for life, while the remainder of the inhabitants of Jerusalem are doomed. The Psalmist likewise speaks of the Book of Life in which only the names of the righteous are written "and from which the unrighteous are blotted out". Even the tears of men are recorded in this Book of God. "Every one that shall be found written in the book . . . shall awake to everlasting life". This book is probably identical with the "Book of Remembrance" in which are recorded the deeds of those that fear the Lord.