Readers who aren't put off by the attribution of ""a strange restlessness"" to the migrating turtles and ""a feeling of fullness"" in one six-foot-long mother-to-be will follow the pregnant wanderer from the shores of Brazil to her egg depository on Ascension Island, then switch to one of her offspring for the return trip. As in the Silversteins' A Star in the Sea (1969), the inevitable sameness of the life cycle formula is relieved by the introduction of some human characters -- here biologists from a floating laboratory who electronically tag the newly hatched turtles and track them for months across the sea. This device is carried a bit far with a boy from the ship who becomes personally attached to one of the turtles, rescuing her from various predators along the way and reencountering her on the same Ascension Island twelve years later when the boy is a marine biologist and the turtle is returning to lay her eggs. On the whole, however, mind-reading the turtles is kept to a minimum and the people do add variety and a bit of scientific information to the long voyage. Allan Eitzen's collages, resembling watered-down Lionni in their marbleized rocks and tissue-crinkly marine backgrounds, don't replace the precision of photographs but they do offer some relief from the bland drawings you often find in books like this.