The Book of Tomorrow by Cecelia Ahern

Tamara Goodwin has always lived in the here and now, never giving a second thought to tomorrow. Until a traveling library arrives in her tiny village, bringing with it a mysterious, large leather-bound book locked with a gold clasp and padlock.
What she discovers within the pages takes her breath away and shakes her world to its core.
A mesmerizing story about how tomorrow can change what happens today.