Philosophy is often viewed as something of an armchair discipline. Biologists and chemists do their research in the lab, anthropologists do their research in the field, historians do their research in the archives. Philosophy of mind sits at the intersection of two big sub-fields of philosophy – metaphysics and epistemology. The method of thought experiment plays an important role in many areas of philosophy of mind – in the debate between dualism and physicalism, in the debate about whether computers can have mentality, and so on. Engaging with thought experiments can help reveal a theory’s hidden commitments and its unrecognized consequences. Arguments against one theory are often taken to be arguments for another, and so having a sense of the big picture puts one in a better position to evaluate each theory individually. The chapter also presents an overview of the key concepts discussed in this book.