The solitaire mystery - Jostein Gaarder

Twelve-year-old Hans and his father have left home to search for Hans's mother. She went to Greece to 'find herself' when he was four. Hans's father loves to philosophise on life (and to drink) and Hans is always happy to listen.
But this turns out to be a strange journey. A dwarf in Switzerland gives Hans a magnifying glass. Next day a baker gives him a bun with a tiny book in it. As Hans begins to read the book, he discovers an incredible cast of characters, from a shipwrecked sailor to a Joker who looks too deeply and too much.
The more he reads, the more Hans begins to think that the book is trying to tell him something about his own life. But will it help him to find his mother?
An incredibly imaginative book, that lingers in the mind long after the last page has been read.