Book excerpt: This “amazing and wonderful book” explores the evolutionary history of photosynthesis in a grand story of how the world became the verdant place we know (Choice). On this blue planet, long before dinosaurs reigned, tiny green organisms populated the ancient oceans. Fossil and phylogenetic evidence suggests that chlorophyll, the green pigment responsible for coloring these organisms, has been in existence for some 85% of Earth’s long history—that is, for roughly 3.5 billion years. In How the Earth Turned Green, Joseph E. Armstrong traces the history of these verdant organisms, which many would call plants, from their ancient beginnings to the diversity of green life that inhabits the Earth today. Using an evolutionary framework, How the Earth Turned Green addresses questions such as: Should all green organisms be considered plants? Why do these organisms look the way they do? How are they related to one another and to other chlorophyll-free organisms? How do they reproduce? How have they changed and diversified over time? And how has the presence of green organisms changed the Earth’s ecosystems? With engaging prose and astonishing breadth, as well as informative diagrams and illustrations, How the Earth Turned Green demonstrates “how the Earth blossomed into such an incredible world that most of us simply take for granted” (San Francisco Book Review).