William Sharpe describes how he became interested in economics and how shifting his UCLA dissertation topic while working at the RAND corporation ultimately led to his work in finance and his derivation of the widely known and widely used Capital Asset Pricing Model (CAPM).  Dr. Sharpe was awarded the 1990 Nobel prize in economics was awarded for his theoretical contributions to finance, especially CAPM.  He credits his time at RAND for his interest in combining theory with practice.  He discusses the unfortunate divide between economics and finance while pointing to economists increasingly using concepts in finance.  His blogs, interviews, and satirical videos are on his website, https://web.stanford.edu/~wfsharpe/