Discover the ancient, invisible language of nature! How did chemical means of communication develop over the course of evolution? Why are chemical signals so crucial for the survival of plants and animals? This nonfiction book takes you on an exciting journey into the world of chemical communication. Billions of years ago, when the Earth was shaken by volcanoes and meteorite impacts, the first living organisms began to use chemical signals in order to survive. This ancient form of communication, known as chemoreception, enabled the earliest cells to find food and avoid dangers. Over the course of evolution, these chemical signals developed further and became an indispensable tool for interaction between organisms. Learn how pheromones, one of the most important classes of biologically active compounds, control animal behavior, and how chemical weapons such as antibiotics and phytoncides are used in the struggle for survival. Discover the fascinating world of semiochemicals, which serve as signaling substances that exchange vital information between organisms. And learn how we humans, too, are part of this chemical communication system. This book is aimed at all those who have an interest in nature and basic knowledge of chemistry and biology. It offers an easy-to-understand, popular-science presentation of chemical communication and shows how these invisible signals influence life on our planet.