This chapter introduces Part II, on Pierre Bayle. It provides an intellectual-biographical account of Bayle’s career, emphasising both his deep immersion in circles of Reformed scholars and theologians, and the reactive dimension of his writing, which were almost always shaped by his most recent reading. It urges caution about trying to find a coherent system in all of Bayle’s writings, and instead presents a framework for a developmental account of his thought. It also introduces the historiographical debate about Bayle, and the so-called ‘Bayle enigma’. It suggests that that enigma can be dissolved even if we carefully place Bayle in his own context, and avoid misleading categories such as ‘scepticism’ and ‘fideism’.