Abstract: A multilayer microelectronic module assembly has at least two planar module structures, in the form of boards lying parallel to each other and which must be electrically interconnected. Each planar module structure has electronic circuitry thereon and electrical interconnect locations in registry with corresponding electrical interconnect locations on the adjacent planar module structure. The electrical interconnections are accomplished by closely spaced direct electrical interconnectors extending between the respective electrical interconnection locations on the adjacent planar module structures. Each module assembly is preferably affixed to a support. Multiple supports are arranged parallel to each other and electrically interconnected by similar direct electrical interconnectors.