This chapter states the book's main thesis, namely that there are three broad categories of revolutions, each with its causes, processes, and consequences. Spontaneous negotiations start out mainly because of state weakness, which in turn provides space for a social movement. Elite defections and increased state vulnerability lead to the growth of the social movement into a mass-based revolution, whose leaders gradually emerge along the way. If stasis and a negative equilibrium emerge, then the revolution succeeds only through negotiations, therefore precipitating a negotiated revolution. Some revolutions, however, start out as planned takeovers of the state, with self-declared revolutionaries using specific ideological blueprints to capture political power.