This volume is a state-of-the-art survey of the psychology of reasoning, based around, and in tribute to, one of the field’s most eminent figures: Jonathan St B.T. Evans. In this collection of cutting edge research, Evans’ collaborators and colleagues review a wide range of important and developing areas of inquiry. These include biases in thinking, probabilistic and causal reasoning, people’s use of ‘if’ sentences in arguments, the dual-process theory of thought, and the nature of human rationality. These foundational issues are examined from various angles and finally integrated in a concluding panoramic chapter written by Evans himself. The eighteen chapters, all written by leading international researchers, combine state-of the-art research with investigation into the most fundamental questions surrounding human mental life, such as: What is the architecture of the human mind? Are humans rational, and what is the nature of this rationality? How do we think hypothetically? The Science of Reason offers a unique combination of breadth, depth and integrative vision, making it an indispensable resource for researchers and students of human reason.