"Written reports of experts on their study of the first-drafts of individual chapters. I believe that these are among the most interesting portions of this collection, for they demonstrate how learned men work. The criticisms are vital, lively, contentious and always refreshing and enlightening. Observe how a great scholar is willing to track down the most minute detail of an item in order to conform it to his body of knowledge. Observe also how they react to non-scientific writing that touches their field in an indirect way. These pages show the critical mind at work and are to me invaluable. The student can also see that when a writer like me says in a preface, 'Mr. Jones read these pages, but all remaining errors are ascribable only to me,' he means it. Sometimes I was not willing to accept the changes proposed by the great experts. Sometimes I had my own stubborn ideas."