The crisis in the foundations of the exact sciences, which had begun during Poincare's lifetime, did not reach a climax till decades after his death. His analysis of the issues of his time foreshadowed the trend; but, deep as was his insight and broad as was his horizon, even he could not have foreseen the extent and ramifications of the imminent upheaval. No more, for that matter, than a political observer of his time, however keen, could have predicted the World Wars and the social and economic upheavals which followed in their wakes.