William Harris' War and Imperialism (Oxford, 1979) has already received a long review in last year's Journal (70 (1980) 177 f.) by A. N. Sherwin White; but the importance of the book and of its theme clearly justifies further discussion of the essential problems raised. In any case, the review concentrated almost entirely on points of disagreement and hardly stated a position on the general questions raised by Harris' work. What is more the author and his reviewer, sharp though their disagreements may be, seem to share a range of assumptions about the scope of the problem and the appropriate methods of dealing with it; in my view, these assumptions need to be stated and examined.