As Edmund Spenser is traditionally spoken of as the poets' poet and as Gustave Flaubert might with equal justice be thought of as the writers' writer, so Mackenzie King may be thought of as the prime ministers1 Prime Minister. In each instance the appeal is less to the public than to the professional be he poet, writer, or politician. What is common and there is obviously much else beside is mastery of technique. Aspiring writers of poetry or prose can hardly afford to neglect Spenser or Flaubert, for they are writers with a command of imagery, or language, or form from which much that is indispensable to success may best be learned. In the very different field of politics the appeal of William Lyon Mackenzie King is of the same order. He was not a man of profound intellect, he enjoyed power without popularity, he abhorred the spectacular, he had an intriguing but not a commanding personality, and there would be little reason for him to be remembered were it not for his supreme mastery of the techniques of politics. The fact that Mackenzie King was a prime minister longer than any man in British history created a certain presumption that he might have a quite exceptional grasp of the realities behind political power. But until the publication of The Mackenzie King Record*there was no conclusive evidence that this was so. In my view the extracts from Mackenzie King's diary, most skilfully edited by J. W. Pickersgill and comprising the great part of the material in this 700-page volume, supply the evidence that has hitherto been lacking. The lasting interest of the volume and there can be no doubt that it will have a lasting interest lies not in any dramatic revelations about events or how they