In 1974, having for some years studied a monastic scriptorium and library (that of Bury St Edmunds in the twelfth century), I found myself in search of a person, an English man of letters from the same period, whose intellectual life might repay investigation. I found William of Malmesbury, via M. R. James's lecture ‘Two Ancient English Scholars’. To my astonishment and delight, no-one seemed to have followed up the evidence of William's extensive and unusual reading presented by James and by Stubbs before him. My immediate reaction was to begin a card-index of works known to William at first hand, as a means of gaining access to his mental and intellectual world. In due course I was led to study the methods by which he acquired and copied his texts, the use which he made of them (notably as historical sources), his contacts with other libraries and monastic scholars, and his achievement and influence as a writer. The result was a number of articles scattered through nine different journals. The notion of a complete monograph did occur to me as a daunting task, and I owe to Richard Barber the idea that the articles themselves might be usefully made into such a book. Acting upon his suggestion, I found that the articles, put into a rational sequence, formed a reasonably complete and coherent structure. This is not to say that the ‘structure’ amounts to a well-rounded or final portrait of William. For one thing, much remains to be done. It would be possible, for instance, to continue the list of studies of William's sources which form part II of this book, and certainly this would reveal more of his scholarly techniques and attitude. Much more, undoubtedly, could and will be said about William as a historian. But it is also the case that a complete portrait of William will never be realizable; he was too reticent to reveal much of himself to his readers, and there is little evidence outside of his writings to compensate for his own silence. The emphasis of this book is on William's scholarship not merely because that is my own principal interest, but because it is in this, and in very little else, that William reveals himself to us. And it is this, in any case, which constitutes his claim to historical importance.