For three and a half billion years the living creatures of the natural world have been engaged in an increasingly complex and extensive conversation. Cells, tissue, organs, plants, animals, entire populations and ecosystems buzz with communication, incessantly emitting and receiving signals. These signs have been there as long as life itself. They make up the semiosphere, a sphere like the biosphere, but one constituted of messages - sounds, odors, movements, colors, electrical fields, chemical signals - the signs of life. This book examines the radical premise that the sign, not the molecule, is the crucial, underlying factor in the study of life. On this tour of the universe of signs, Jesper Hoffmeyer travels back to the Big Bang, visits the tiniest places deep within cells, and ends his journey with us - complex organisms capable of speech and reason. He shows that life at its most basic depends on the survival of messages written in the code of DNA molecules, and on the tiny cell - the fertilized egg - that must interpret the message and from it construct an organism. What propels this journey is Hoffmeyer's attempt to discover how nature could come to mean something to someone; indeed, how "something" could become "someone." How could a biological self become a semiotic self? And how, finally, do we unite these two different selves, "nature" and "mind" which we all carry in us and which all too often are at war with each other?