"In a real though figurative sense, the book of life is the record of the acts of men as such record is written in their own bodies. …
That is, EVERY thought, word, and deed has an [effect] on the human body;
all these leave their marks, marks which can be read by Him who is Eternal as easily as the words in a book can be read”
(Mormon Doctrine, 2nd ed. , 97).