A funny vacation tale, perfect for summertime story hours, from the creator of that other traveling dog, Amos: The Story of an Old Dog and His Couch (1987, not reviewed). The biggest problem of the Arbuckles' family vacation is how to include Mercer, the family pup, in hotels that explicitly state ``No dogs allowed.'' Disguising the hound as a French gentlemanMonsieur D'Puppieis the temporary solution, at least until Madame Croissant tries to speak French to poor Mercer. The book skips along on a course of near-miss discoveries of the canine impostor by the veterinarian, other hotel guests, and the management. Mercer makes a funny-looking Frenchman, and tolerates it nicely, but revels in the moments when he can go down on all fours again. Rollicking illustrations will make children giggle, while the plot will keep them in suspense over whether Mercer's secret will be spilled, right up to the frantic happy ending. (Picture book. 4-8)