Alfi may be afraid of the Dark when it's time to go to sleep, but he's also a philosopher: he wonders where the Dark goes when the light is switched on. So begins a dialogue with the dreaded adversary, pictured as a misty, evanescent shadow that may speak (except when ""his thoughts were elsewhere"") and that is sometimes lonely, sad, and in need of a friend. The answer to Alfi's question--that Dark doesn't actually go anywhere, but is invisible where there is light--is satisfying to the poetic imagination, if not to the scientific one; children will be unaware of the author's more ominous meaning (she was terminally ill when the book was written) while responding to the sense of mystery. The idea here is more interesting than Miles' rather awkwardly rhymed couplets; but the book's best feature is Le Cain's masterful illustrating. With lurching perspectives and looming shadows, he conveys the awesome transformation of the familiar that children experience in the dark--yet wide-eyed Alfi himself is always warmly safe, more curious than frightened. An interesting addition to the monsters-at-bedtime canon.