If a butterfly stirs its wings in Brazil, does it cause a tornado in Texas? Chaos is the most important advance in science since the advent of Quantum Theory. The discovery of randomness in apparently predictable physical systems, has evolved into a new science that declares the universe to be far more unpredictable than we could have imagined. Continuing the now familiar format of the Introducing... series, this book documents how chaos is present in most events, from the fluctuation in small animal populations to the rise and fall of financial markets.