This chapter describes how events in Naxalbari in West Bengal and Srikakulam in Andhra Pradesh gave birth in India to a left-wing extremist movement, based on the teachings of Mao-Zedong. It discusses the organisation of this movement, how it splintered but then coalesced into two main groups, and how it spread from one state to another. It analyses the Indian government’s response to this form of terrorism.