The 15 chapters in this book include commentaries on 12 seminal works on self-directed learning (SDL) by Houle, Knowles, Tough, Spear and Mocker, Brookfield, Caffarella and O'Donnell, and Long et al. These works were identified by a Delphi panel of 49 experts. Chapter titles and authors are as follows: "An Introduction to the Study of Self-Directed Learning" (Confessore); "SDL in the Workplace" (Confessore); "Selecting the Key Literature in SDL" (Confessore, Confessore); "Inquiring Mind: A Study of the Adult Who Continues To Learn" (Candy); "SDL: A Guide for Learners and Teachers" (Long); "Major Learning Efforts: Recent Research and Future Directions" (Bonham); "The Adult's Learning Projects: A Fresh Approach to Theory and Practice in Adult Learning, 2nd Edition" (Kasworm);"Learning without a Teacher: A Study of Tasks and Assistance during Adult Self-Teaching Projects" (O'Donnell); "The Organizing Circumstance: Environmental Determinants in SDL" (West); "SDL: From Theory to Practice" (Hiemstra); "Understanding and Facilitating Adult Learning" (Guglielmino); "Self-Directed Adult Learning: A Critical Paradigm Revisited" (Spear); "SDL: Application and Theory" (Knowles); "SDL: Emerging Theory and Practice" (Tremblay); and "Advances in Research and Practice in SDL" (Danis). (SK)