Introduction to the theory of complex systems: by Stefan Thurner, Rudolf Hanel and Peter Klimek, Oxford, Oxford University Press, 2018, 431 pp., £49.99 (hardback), ISBN 978-0-19-882193-9. Introduction to the theory of complex systems, by Stefan Thurner, Rudolf Hanel and Peter Klimek Oxford, Oxford University Press, 2018, 431 pp., £49.99 (hardback), ISBN 978-0-19-882193-9. There follow highly detailed and carefully structured chapters on probability/stochastics, scaling, networks, evolutionary processes, and statistical mechanics/information theory. [Extracted from the article]