My aim in this book is to introduce you to the main theses, concepts and arguments in Plato's philosophy. Subtle, versatile and multifaceted though Plato's thought undoubtedly is, it has a core that needs to be explored and savoured. My purpose is to present this core, as it appears over a large range of his works, spread out over many decades of composition and many philosophical topics. Through all this diversity Plato's very original philosophical personality shines through.

I approach the material thematically, in terms of modern philosophical categories, in the seven main chapters. But within each of these individual treatments I follow the lines of argument in the main works of Plato that explore them. Every topic that I address can be and has been much more widely discussed in the scholarly and philosophical literature on Plato. I give indications about how to pursue these enquiries in Further Reading sections at the end of each chapter and the Bibliography. It is my hope that the initial steer to the understanding of Plato that is given in this book will point you in the right direction.

My many intellectual debts are far too numerous and complex to acknowledge here. Steven Gerrard, Publisher of Acumen, has been a good source of support; and Alan Weir's technical expertise has been invaluable. A deeper and more extensive debt is to generations of students, at the University of Cambridge, Duke University (North Carolina) and Queen's University Belfast, on whom over nearly five decades I have pressed my ideas and who have responded in appropriately critical manner.