Ambrose was one of the auditors to whom Wittgenstein dictated what came to be known as the Blue and Brown books between 1933 and 1935, and she prepared the final typescripts of both. With Margaret Masterman she also took down his lectures for what Ambrose called ‘The Yellow Book.’ Ambrose published her own notes of these lectures in her edition of Wittgenstein’s Lectures, Cambridge, 1932-1935, (1979).
‘This collection contains research material for several doctoral dissertations and books. Anyone interested in the development of Wittgenstein’s post-Tractatus philosophy will find a wealth of leads to follow up. To have notes recording the way a first-rate philosopher was thinking almost day by day is extremely rare in philosophy, and here we have a record of Wittgenstein’s changing thought over a period of three years or more. What is more it was the very period during which he was developing the core ideas of his later philosophy. A careful study of the documents in this collection is bound to lead to a better understanding of the development of his later philosophy. …The period that this collection covers is now of great historical interest and is bound to be studied extensively in the coming decades. It is to be hoped that this rich collection will find a home in one of the great research libraries where it will receive the care, protection and, most importantly, the use that it deserves’ – John G. Slater, Professor of Philosophy, Emeritus, University of Toronto.