Based on expert consensus of 67 RT experts through the ATRA Delphi Study, a list of specific diagnostic populations served, interventions/modalities, techniques, standardized assessment tools, theories, education/training/ counseling topics utilized, and on-the-horizon treatment and issues were identified. This manuscript provides an overview of the study and its findings. The content from the ATRA Delphi Study was utilized to create the ATRA Competencies Study that was disseminated internationally to determine the extent that each item is currently served/utilized in practice, the extent of self-perceived knowledge and skills of each item, and the extent of interest in gaining more knowledge and skills related to each item. An overview of the ATRA Competencies Study and the findings are shared in a separate article.