In adult English-as-a-Second-Language literacy education and staff development, practitioner inquiry has emerged as a powerful approach toward improving practice. A variety of activities occur under the umbrella of practitioner inquiry, all of which are grounded in the knowledge and questions held by practitioners. The characteristics of inquiry intersect with those of other adult education concepts such as self-directed learning, reflective practice, learner centeredness, and action research. Inquiry has been defined as a "social and collaborative process" through which practitioners actually contribute new knowledge within programs and even to the larger adult education field. This digest examines the thinking that underlies practitioner inquiry, explains the phases of an inquiry process, and gives examples of projects. The digest concludes by identifying concerns with the approach and by suggesting changes that must take place if inquiry is to be viably implemented as a staff development process. (VWL) (Adjunct ERIC Clearinghouse on Literacy Education)