Window peeping is encouraged in this alphabet book of 26 acetate openings; a letter labels each transparent window. By pulling a tab at the bottom of the page, a blind lowers and the letter seems to melt into the illustration behind it. J makes an appropriately curved tail for a jaguar perched on a limb, while B is transformed into a baby sitting in its crib. The illustrations are flat and generic; the pull-tabs will soon be mutilated in an institutional setting. What sells the book is the low-tech morphing of letters into images, and back into letters again. (Board book. 3-7)