In this gothic novel set in modern times, 16-year-old Tamara Goodwin tells her story, first admitting that many people will greet it with disbelief. Her once incredibly wealthy father has committed suicide. He leaves his daughter, grappling with guilt and sorrow disguised as anger, and his adored wife, who has consequently lost touch with reality. Tamara and her mother have no money now because of her father's financial losses. They leave their fabulous Dublin home and luxurious life to live with Aunt Rosaleen and Uncle Arthur in the gatehouse to a castle ruin, in the middle of nowhere.

According to Rosaleen, Tamara's mum is simply grieving. Tamara's opinion is that her mother (who rarely leaves her bed) is in need of a mental hospital. Bored to death, Tamara checks out the ruins of the old castle on the grounds, where she catches a glimpse of a mysterious figure. Back at the house, she tries to wade through an enormous breakfast while figuring out how she can possibly fill up her summer hours after learning that the only nearby town is too far to walk to.

Imagine Tamara's pleasure when, with Rosaleen away, a handsome young man appears at the door. Marcus is the driver of the mobile library, and their mutual admiration is at full throb as he offers Tamara a ride into "town." Tamara is devastated when she sees how tiny the village is, and then overjoyed when Marcus saves the day by suggesting they use their imaginations and the books in his bus to "travel" to Mexico together. Later, as Marcus helps a reader find a book, Tamara discovers quite the unusual volume while browsing the library's shelves. The book is large and bound in leather, lacks an author's name and title --- and is locked with a small gold padlock. She can't resist borrowing this intriguing tome.

Tamara's time with Marcus is interrupted by Rosaleen and Arthur, who have searched for and found her in town. She is not only reluctant to leave the adorable Marcus, as she lugs the mysterious book into their car, but she also briefly wonders why the villagers gawk at her aunt and uncle.

The death of her father is never far from Tamara's mind. She believes her ugly behavior immediately before he killed himself might well have contributed to his decision to act. As she ponders her guilt, she wonders: If you could predict the future, could you (and should you) try to improve it? Having opened the mysterious book and discovered it has blank pages, she decides she will keep a journal. But as she prepares to write her first entry, she finds something beyond mysterious. The previously blank pages are now filled --- with her own handwriting. The entry is dated the next day. Her bewilderment is compounded, as the events recounted in the journal entry begin to unfold, exactly as described. Is this her opportunity to change her future?

THE BOOK OF TOMORROW offers an intriguing premise, a backstory filled with captivating mysteries, and a sympathetic main character. While some may find the chapter explaining the mysteries in Tamara's story rather long and didactic, others are likely to enjoy the thorough clarification. All should agree, however, that Cecelia Ahern, as she has done in her previous books, continues to fearlessly tackle enormous ideas in imaginative ways, giving readers yet another enjoyable read.