Revision with unchanged content. A shift in the models of treatment and treatment settings in the developmental disabilities field over the past few decades has expanded the need for professional development trainings. Despite an increase of research due to this expanding need, few studies exist on the learning characteristics of developmental disabilities professionals. The purpose of the present study is to investigate patterns of learner preferences, defined as professionals’ learning styles and loci of control, among personnel involved in professional development in the developmental disabilities field. This analysis should assist those who develop and deliver education/training to developmental disabilities professionals better address the learning preferences of this population. This book is intended for researchers and professionals interested in the education and training of developmental disabilities professionals. This includes professional development researchers, college faculty, professional development faculty/trainers who work with developmental disabilities professionals, developmental disabilities direct care staff, and human service administrators.