This paper explores the readiness of student affairs professionals to utilize adult development knowledge in everyday interactions with college students. Four types of knowledge about the adult development process (cognitive-developmental, psychosocial, person-environment interaction, and humanistic-existential) are briefly defined, with references cited for further reading. A discussion of the author's presumptions or judgments about the usefulness of adult devlopment knowledge, using commonly held criteria for evaluating theory (explanatory power, parsimony, comprehensiveness, simplicity, assessment of development, and compatibility with students), is presented. Evidence supporting the author's judgments of usefulness in practice is given in the text, while the actual judgment values, low or high, are given in Table 1. A discussion of the author's presumptions about practitioner readiness to use this knowledge in student affairs is also presented, focusing on attitudes, willingness, desire to improve, depth of knowledge, measurement competencies, resources, professional time, and time frames for development. Evidence in support of each presumption or judgment is provided and the judgment values are given in Table 2. A case study, focusing on a year-long orientation program for college freshmen is presented to illustrate the concept of developmental programming. Stages in model development, including theory exploration, question formation, measurement instruments, objectives, and intervention, are discussed. The paper concludes with comments on the profession's readiness and issues for further analysis. (BL)