A book in which every life is written is traditionally read as a reckoning with your own story. It points to the wish to be remembered, and to a quiet review of what you have done and left undone.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.