WHO'S AT THE DOOR?

It's the shifty-eyed wolf at the pigs' door, but neither his several disguises (a blowzy old lady; a policeman) nor the mendacious reasons he offers for coming in (``I've locked myself out...Can I...use your phone?''; ``There's a suspicious old lady in the area'') deceive the three pigs; once they've had enough, they concoct their own disguise and frighten the wolf away with a satisfyingly clever role reversal. Allen (who perpetrated the comical illustrations for Mahy's The Great White Man-Eating Shark, 1990) extends the fun with split pages representing the pigs' door, which opens to reveal each new disguise. A winning and funny variation on an old theme. (Picture book. 3-8)