Inadvertently an error crept in, at proof stage, to Dr J. R. Pole's article: we apologize to him and to our readers for this, and we would like to correct it. On page 69 the sentence to which footnote I refers should, of course, read ‘George F. Kennan's trenchant critique…was followed shortly by Professor John M. Blum's…’ As it stands, the text is wrong, the footnote is correct.