At no time in U.S. history has there been a more effective challenge to medical expertise and authority than that mounted by the contemporary Laetrile movement. The efficacy of Laetrile has been debated for over twenty-five years, but despite vigorous opposition from the medical community, support for the purported cancer treatment continues to grow and the controversy has in recent years intensified and become highly politicized. How does one account for the continuing debate and the spectacular political growth of the movement to promote Laetrile? This and related questions are addressed by an interdisciplinary group of authors in this first scholarly analysis of the Laetrile phenomenon.