Abstract: The present invention's composite-to-metal attachment methodology—bolt-free and adhesive-free—features the implementation of an intermediary structure containing metallic fibrous material. The intermediary structure couples a first adherend (which contains nonmetallic fibrous material) with a second adherend (which contains metallic nonfibrous material). The intermediary structure's fibrous attribute is availed of for effecting its co-cure attachment to the first adherend. The intermediary structure's metallic attribute is availed of for effecting its weld attachment to the second adherend. According to typical inventive practice, respective panels of the first adherend and the intermediary structure are arranged and connected so as to describe a stepped configuration at the interface between the first adherend and the intermediary structure. The first adherend and a first portion of the intermediary structure are co-impregnated with a uniform resinous system and are co-cured.