The theoretical defensibility of applied linguistic intervention design provides the rationale for such designs, demonstrating how they are supported by theory, constructs, and analysis. Though founded upon science, imaginative design has its leading technical function as guiding lodestar. A scientific rationale for a plan underwrites the design, but does not qualify it, as is attempted in technicism. The logical-analytical retrocipations in the structure of the technical sphere act as normative endorsement. On the factual side, analyses of the empirical properties of designs give them a further analytical boost. The technical-theoretical approach demonstrates that designs are accomplished with logic and analysis. [For the complete volume, "A Theory of Applied Linguistics: ?magining and Disclosing the Meaning of Design. Educational Linguistics. Volume 65," see ED672528.]