The Thirteen Clocks, by James Thurber, illustrated by Marc Simont, originally published by Dutton, 1950, reprinted by The New York Review, 2008. All ages.
This book is about as perfect as any book can get. Written by James Thurber, illustrated by Marc Simont, and introduced by Neil Gaiman. It is not quite a fairy tale; not quite a fable; not quite a ghost story, and it is quite, quite perfect.
There is a villain, whose flaw is "being wicked". There is a hero-prince-minstrel, whose name starts with an X, but doesn't start with an X. There is a beautiful princess, who is "warm in every wind and weather". There is a mysterious Golux. And there are thirteen clocks, that are stopped, because the villain murdered Time and wiped his blade on Time's beard. And there are the shining shores of Ever After.
This book is perfect, and perfect for all ages.