Spoil me and when I said spoil it for me it means give major spoiler

Here for the spoiler~

.
.
.
.
So I haven't read it myself but from what I have gathered she was OG Sylvia and made a contract with the devil to rewind time. Her modern life was a reincarnation between her 2 Sylvia lives (Doctor Elise style). The book she is thinking of are actually her original memories. That is all I am certain enough to report on