Jenny's father explains the 17-year cicadas' life cycle and tells her about the last time they appeared (he was 12); together, they observe and admire the insects' during their brief appearance. By extending the story another 17 years, Ryder links the cicadas' cycle to Jenny's: now she and Dad can share this special natural event with Jenny's son. Ryder's text is graceful as well as informative; Stock's gentle illustrations not only reinforce the warm family relationship but serve to identify the cicadas at different stages. (Picture book. 5-9)