This informative addition to the Footprints series discusses the environmental consequences of light pollution. A biologist and science writer, Aitken points out that plants and animals on Earth evolved over millions of years in an environment with dark nights. For some species, darkness is vital to survival. But over the last century, electric lighting has brightened the nights in many areas and eroded the darkness. Animals rely on darkness for safety from predators when foraging, mating, and building their homes. Trees in brightly lit cities have longer growing seasons, making them more vulnerable to frost damage. Artificial light affects people as well, disrupting the circadian rhythm and interfering with sleep. One of Aitken's strong points is his ability to make statements about broad concerns and back them up with several pertinent examples, showing how particular animals or plants are threatened by artificial lighting in specific ways. Well-chosen color photos appear throughout the book. One of the few children's books focused on light pollution, this organized, involving book will fill a gap in many library collections.

An overview of the effects of artificial light on nature and us.Aitken notes that many wild creatures are confused by increased levels of nighttime illumination-after all, as he states, half of all invertebrates, 3 out of 4 mammals, and nearly all amphibians are nocturnal. At times, he gets a bit off message, allowing that many bats enjoy the "all-you-can-eat bugfest" around streetlights; he also discusses how 3 out of 4 sea creatures naturally glow in the dark and that miners have used fireflies and dried fish skins for light. However, his laments for the loss of unobstructed views of the night sky and the deaths of millions of bird colliding with lit windows, his warnings about the effects of blue (but not yellow) LED lights on our levels of melatonin, and his reports on how brighter security lights cause crime levels to rise-and vice versa-are well taken, and he does close with a sensible invitation to young nature lovers to flick the switches off and "take a walk on the dark side." Color photos supply views of densely starry skies, lit up cityscapes, wildlife, and diverse sets of human observers.Veers off course occasionally but flashes on a too often unconsidered sort of environmental pollution. (resource lists, glossary, index) (Nonfiction. 9-12)