"How much light is too much light? Satellite pictures show our planet as a brightly glowing orb, and in our era of constant illumination, light pollution has become a major issue. The world's flora and fauna have evolved to operate in the natural cycle ofday and night. But in the last 150 years, we have extended our day-and in doing so have forced out the inhabitants of the night and disrupted the circadian rhythms necessary to sustain all living things, including ourselves. In this "well-researched andsurprisingly lyrical" (The New Statesman, UK) book, Swedish conservationist Johan Eklöf urges us to appreciate natural darkness, its creatures, and its unique benefits. He ponders the beauties of the night sky, traces the errant paths of light-drunk moths and the swift dives of keen-eyed owls, and shows us the bioluminescent creatures of the deepest oceans. As a devoted friend of the night, Eklöf reveals the startling domino effect of diminishing darkness: insects, dumbfounded by streetlamps, failing toreproduce; birds blinded and bewildered by artificial lights; and bats starving as they wait in vain for insects that only come out in the dark. For humans, light-induced sleep disturbances impact our hormones and weight, and can contribute to mental health problems like chronic stress and depression. The streetlamps, floodlights, and neon signs of cities are altering entire ecosystems, and scientists are only just beginning to understand their long-term effects. The light bulb-long the symbol of progress and development-needs to be turned off"--