Final answer:
Professor Merton Miller received the Nobel Prize in Economics for his work on capital structure theory.
Step-by-step explanation:
Professor Merton Miller received the Nobel Prize in Economics for his work on capital structure theory. This theory focuses on the mix of debt and equity financing that a company uses to finance its operations and investments. Miller's work was groundbreaking because it showed that, under certain conditions, the value of a firm is not affected by its capital structure.