The purpose of this study was to investigate the characteristics and means of Katinka Dániel's interpersonal influences through the perceptions of 20 selected students, protégés, and colleagues, and to study the behavioral and attitudinal changes they attributed to her influence. A case study design and structured interview questionnaire were used to study four variables coming from the social sciences' literature on influence: legitimate authority, attractiveness, expert authority, and trustworthiness. Responses were qualitatively analyzed to determine the role those variables played in Dániel's interpersonal influence. All interviewees were music teachers who used the Kodály method in their teaching and have studied or worked with Dániel. Two images of Dániel emerged from the interviews. The first, a business-like image, emanated from Dániel's work in the classroom, and the second, a maternal image, came from personal relationships with her students and associates. Attractiveness (defined as a willingness to respond positively to the requests of an influential person because one respects that individual and wants to obtain that person's approval) proved to be the principal characteristic of influence, followed by legitimate authority, then expertise. Trustworthiness played a lesser role. The greatest effect of Dániel's influence was on the interviewees' teaching. Among the factors interviewees described as influential were her expectation they would succeed, her position as role model, praise and encouragement, and gestures of generosity and concern. Interviewees were not in agreement as to whether she used persuasion or coercion. Direct verbal communication served a principal role in Dániel's influence, and though her criticism was described as forthright and bluntly honest, interviewees often accepted it. This was because most believed she was focused on their best interest, because her motives were not considered self-serving, and because they saw the reasons for her criticism as stemming from her high ideals and the desire to see them improve as teachers. The dissertation includes a biography of Dániel.