Management consultancy practice is particularly concerned with helping clients implement strategic organisational change. But what exactly are organisations, and management consultancy interventions in them? Management consulting is said to be a knowledge-intensive industry. But what kind of knowledge do management consultants possess, and how far can we rely on it? Management consultants are often criticised for unethical exploitation of their clients. But how ought management consultants to behave in order to meet acceptable ethical standards? These are questions about the philosophical topics of ontology, epistemology and ethics. The ancient Greek philosophers thought deeply about these topics, and their ideas remain fresh and relevant even to so modern a subject matter as management consulting. Writing between the end of the sixth and the end of the fourth century BCE, these philosophers were drawing upon an intellectual tradition that was very different from our own, and were responding to social and economic conditions that were wholly unlike ours. Approaching these philosophical questions from a perspective that is radically different from our own, their work provides a rich resource for novel thinking about management consulting. From the speculations of the Presocratic philosophers Heraclitus, Parmenides, Leucippus and Democritus about the nature of the universe to the thought of Socrates, Plato and Aristotle about the nature of human beings, this book uses the work of these great thinkers as a lens through which to study major philosophical questions about management consulting. Examined in this way, many established assumptions and principles of management consultancy practice seem questionable, and new ways of thinking possible.