The Solitaire Mystery by Jostein Gaarder

Twelve-year-old Hans Thomas and his father are driving from Norway to Greece in search of Hans Thomas's mother, who left them many years before. Along the way, the boy receives a mysterious miniature book - the fantastic memoir of a sailor shipwrecked in 1842 on a strange island where a deck of cards has come to life. But what does the sailor's journey have to do with that of Hans Thomas? And what can both their journeys tell us about our own quest to understand life?