In a wonderful synthesis of science, history, and imagination, Gino Segrè, an internationally renowned theoretical physicist, embarks on a wide-ranging exploration of how the fundamental scientific concept of temperature is bound up with the very essence of both life and matter. Why is the internal temperature of most mammals fixed near 98.6°? How do geologists use temperature to track the history of our planet? Why is the quest for absolute zero and its quantum mechanical significance the key to understanding superconductivity? And what can we learn from neutrinos, the subatomic “messages from the sun” that may hold the key to understanding the birth-and death-of our solar system? In answering these and hundreds of other temperature-sensitive questions, Segrè presents an uncanny view of the world around us.