Malcolm Shepherd Knowles was a key writer and theorist in the field of adult education in the United States. He died in 1997 and left a large legacy of books and journal articles. This thesis traced the development of his thinking over the 46-year period from 1950 to 1995. It examined the 25 works authored, co-authored, edited, reissued and revised by him during that period. The writings were scrutinised using a literature research methodology to expose the theoretical content, and a history of thought lens to identify and account for the development of major ideas. The methodology enabled a gradual unfolding of the history. A broadly-consistent and sequential pattern of thought focusing on the notion of andragogy emerged. The study revealed that after the initial phases of exploratory thinking, Knowles developed a practical-theoretical framework he believed could function as a comprehensive theory of adult learning. As his thinking progressed, his theory developed into a unified framework for human resource development and, later, into a model for the development of self-directed lifelong learners. The study traced the development of Knowles’ thinking through the phases of thought, identified the writings that belonged within each phase and produced a series of diagrammatic representations showing the evolution of his conceptual framework. The production of a history of the development of Knowles’ thought is the major outcome of the study. In addition to plotting the narrative sequence of thought-events, the history helps to explicate the factors and conditions that influenced Knowles’ thinking and to show the interrelationships between ideas. The study should help practitioners in their use and appreciation of Knowles’ works.

Early childhood education (ECE) teachers often lack the experience and skills to provide children with supports necessary to foster academic and social skill development. Professional development can improve ECE teachers' skills, but ECE trainers often lack understanding of adult learning principles, known as andragogy. Knowles' conceptual framework of andragogy was used to explore the knowledge and use of andragogical principles of 8 ECE trainers selected via criterion-based purposive sampling. The research questions focused on ECE trainers' knowledge and use of andragogical principles. Three cases, each consisting of 2 or 3 live professional development trainings for early childhood educators, were used in this study. Data sources included (a) observations of ECE trainings, (b) semi-structured interviews with ECE trainers, and (c) content analysis of ECE training materials. Thematic analysis revealed that although participants were not formally trained in andragogy and were unfamiliar with the associated verbiage, most had a strong grasp of andragogy and used andragogical principles to drive the development and presentation of their training materials. The 3 main themes that emerged were (a) lack of training/background in andragogy, (b) training strategies employed, and (c) training design. Findings from this study provide an original contribution to the limited existing research on the professional development of early childhood educators and expand the existing body of research on andragogy. This study contributes to social change by revealing that trainers may benefit from formal andragogical training, which may then improve the education provided by ECE teachers to young children.