Use of self is a concept that is universally accepted yet equally ambiguous. Melding the professional self of what one knows (training, knowledge, techniques) with the personal self of who one is (personality traits, belief systems, and life experience) is a hallmark of skilled practice. This paper synthesizes seminal works regarding the concept of use of self and suggests a five-category typology for defining and describing use of self in social work practice. Drawing from the literature and practice wisdom gleaned from the author's clinical, teaching, and supervisory observations, the article proposes that use of self can be operationally defined as: use of personality; use of belief system; use of relational dynamics; use of anxiety; and use of self-disclosure.