For composite systems, design is an enabling technology for manufacturing, and manufacturing is a critical element of design. The present paper will explore this relationship for advanced composite materials, especially continuous fiber reinforced materials. The primary subjects addressed include the design of nano-structures in the polymer matrix of polymer composites, especially for toughening of the composite system; design of interfaces/interphases to enable manufacturing of durable composites; design of ply orientations to enable manufacturing of defect-free composite laminates; and choice of manufacturing parameters for design of durable composites, and tradeoffs of those parameters vs. performance.