This book presents an argument rather than a narrative survey. The premiss of the argument is that from the high Middle Ages onwards, physicians built up their trade into an elaborate professional stucture, endowed it with an even more elaborate theory, and contrived to present it with great authority. Some physicians became rich, others famous and powerful, as teachers and practitioners. Great households retained physicians as part of the ‘family’ and towns sought out university-trained physicians for contract-based employment.

Many physicians were, then, successful. We have no way of measuring their clinical success, for that would be to ask modern questions and expect modern answers from inappropriate historical material. Moreover, our instinct is to believe that old medicine was less effective than our own, which is so conspicuously scientific. Indeed, from a modern viewpoint pre-scientific medicine can look ridiculous in its theory and bizarre and disgusting in its remedies. How, then, did physicians in the past meet the expectations of their society, and so succeed?

The argument of this book is that they did so partly by helping to create those expectations, which were accordingly easier to satisfy. The fully trained university doctor had two main methods of cultivating his image as a capable medical man, his reason and his learning. These two characteristics will often be capitalised in this book to show that they are technical terms in a historical sense.