Behaviours change culture, not the other way around. The spread of behaviours is the real source of social change. Behavioural imitation explains how social change happens, how epidemics of ideas are formed, how social fashions appear and how company cultures shape and reshape themselves. The spread of behaviours is also viral in nature. In his pioneering book, 'Viral Change,' Leandro Herrero begin_of_the_skype_highlighting end_of_the_skype_highlighting addressed how a relatively small number of highly connected individuals could orchestrate change in an organisation through a small set of non-negotiable behaviours. In his new book, the author now addresses Viral Change in action, showing that the more primal 'Homo Imitans' is still a powerful force. Understanding how social, behavioural infection works is the basis for the orchestration of any 'epidemic of success', be it a successful change inside a firm or a counter-social epidemic to tackle negative socio-macro phenomena.