Purpose: This paper aims to explain the nature, and identify the quality criteria of a doctoral thesis by explication for professional management development. Design/methodology/approach: A working definition of a professional doctoral explication thesis (DET) is proposed and substantiated by five experts. The paper takes a practical, educational approach to senior executive development through action learning and explication writing; and it briefly explains the philosophical assumptions underpinning the practice of explication writing, including grounded theory, personal construct theory, critical theory, and systems theory. Findings: The paper identifies the main principles affecting the quality of a thesis, the main characteristics of a DET, the differences between a DET and a PhD thesis, and the differences between "researching" and "writing" an explication. Research limitations/implications: Length of a journal article severely restricts capacity to explain in detail how to write, supervise and examine a DET. With these limitations, this paper presents a rationale for, and new conceptual models of, both knowledge creation and a thesis by explication. Practical implications: The paper offers a practical checklist for candidates, supervisors and examiners for evaluating the quality of a DET, the published works supporting it, and the oral examination. Originality/value: The contributions relate to first, conceptual models of knowledge creation, explication research activities and explication writing; and second, a practical checklist mentioned above. (Contains 3 figures and 4 notes.)