The Search for Financial Security. By Robert B. Warren. New York: Columbia University Press. 1940. Pp. viii, 91. ($1.25) - Liquidity and Instability. By Courtney C. Brown. New York: Columbia University Press. 1940. Pp. xvii, 282. ($3.00) - The Stock Market, Credit and Capital Formation. By Fritz Machlup, Translated from a revised version of the German edition by Vera C. Smith. London, Edinburgh, Glasgow: William Hodge and Company [New York: Macmillan Company]. 1940. Pp. xii, 416. ($5.00)