The celebrated husband and wife team originally compiled this introduction to nature for their own young son, Ola. More than 50 animals from the polar regions to the tropics are beautifully lithographed in full color in lovely settings. Sure to delight the youngters, read the book the usual way, page-by-page, or unfold it for an eight-foot-long panoroma of zoological wonder.  (NAT116, $16.95)