The problem under investigation in this study is the determination of the usefulness of the concept of saving set forth by John M. Keynes in his The General Theory of Employment, Interest and Money, both as a method of prediction and prevention of business cycles and as a conceptual framework which is for use in explaining past economic activity, particularly economic growth. The study has a twofold purpose. The first is to evaluate the workability of the Keynesian definitions when applied to existing sources of economic data; to see if a meaningful savings aggregate is a statistical possibility. The second is to attempt to explain in terms of related parts of the rest of Keynes' theoretical system the conclusions reached under the first purpose above.