From ecosystems to Facebook from the Internet to the global financial market some of the most important & familiar natural systems & social phenomena are based on a networked structure It is impossible to understand the spread of an epidemic a computer virus large-scale blackouts or massive extinctions without taking into account the network structure that underlies all these phenomena In this Very Short Introduction Guido Caldarelli & Michele Catanzaro discuss the nature & variety of networks using everyday examples from society technology nature & history to explain & understand the science of network theory They show the ubiquitous role of networks; how networks self-organize; why the rich get richer; & how networks can spontaneously collapse They conclude by highlighting how the findings of complex network theory have very wide & important applications in genetics ecology communications economics & sociology ABOUT THE SERIES The Very Short Introductions series from Oxford University Press contains hundreds of titles in almost every subject area These pocket-sized books are the perfect way to get ahead in a new subject quickly Our expert authors combine facts analysis perspective new ideas & enthusiasm to make interesting & challenging topics highly readable