In very simple words and excellent pictures, the author and illustrator juxtapose the growth and maturity rate of four appealing animals -- the gorilla is compared to the lamb, the sparrow with the duckling. The stories of the growth cycles are told simultaneously with contrasting colors of print, and of course the pictures help keep things straight. The illustrations are photographically clean in line and detail and the author has done her usual exceptional job of making information both clear and interesting in an easy vocabulary.