Problem-based learning has become a widespread teaching methodology in disciplines where students must learn to apply knowledge, not just acquire it. This volume describes the basics of the method, along with the variables that affect its success. The chapters provide examples of its application in a wide range of disciplines, including medicine, business, education, engineering, mathematics, and the sciences. The authors make a persuasive argument that professional fields as well as academic fields would find much to recommend PBL as a standard teaching method. This is the 68th issue of New Directions for Teaching and Learning.