This paper attempts to trace a line of theory development in technical communication from Dwight Stevenson's 1977 call for "instrumental effectiveness" in theoretical inquiries, based upon careful inductive research methods, to later examples of more speculative and inadequately documented theories about what constitutes the field's intellectual domain. While acknowledging the importance of interdisciplinary inquiry, the paper critiques some inquiry approaches for: (1) an excessive deviation from necessary traditional constraints on the field's legitimate inquiry domain, and for (2) an excessive reliance on composition studies theory for specific intellectual guidance. The paper argues for a restoration of more field-appropriate theory-building as articulated by Stevenson, Anderson et al.; one based upon the constraints of inductive evidence and instrumental effectiveness. Twenty-seven notes are included. (Author/PRA)