The outsider who presumes to instruct specialists in the needs of a field which is theirs and not his is very like the bachelor who dares to lecture parents on the requirements of child-rearing: having learned everything secondhand, he is in frightful danger of talking nonsense and, what is worse, of thinking it sagacity.

Two things encourage me to undertake the risk: (1) The difficulties which beset the study of international politics do not seem to me peculiar to that field alone, but are encountered firsthand and in substantially the same form in other fields of which I have direct knowledge. (2) It is apparent from even a casual exposure to the field that its own practitioners are currently in a stock-taking mood in which they seem eager to scrutinize their own product and to have its value assessed. This mood of disquiet has also begun to express itself in proposals for new general approaches to the field, new areas of inquiry, new schemes for collating and analyzing data, explorations into questions once thought remote from the concerns of international politics, and other such developments signifying vitality and a lively spirit of inquiry. The two works which provide the occasion for this essay are items in point, but many others could be cited.