An adventure story tracing the mystery of our planet’s beauty in three parts: a quest to find blue—one of the rarest of colors in nature—out in the natural world; a compelling meditation on blue’s impact on our culture, language, and the author’s own life; and a fascinating look at the science behind how this rare wavelength of light works. From the rain forest’s morpho butterfly to the blue jay flitting past your window, few living things are blue. Science journalist Kai Kupferschmidt has been fascinated by blue since childhood. In Blue, his quest to understand the science and nature of his favorite color takes him from a biotech laboratory in Japan and a volcanic lake in Oregon to Brandenburg, Germany— home of the last surviving blue-feathered Spix’s macaws. Whether it’s deep underground where blue crystals grow or miles overhead where astronauts gaze down at our “blue marble” planet, wherever we do find Earth’s rarest color, it always has a story to tell.