The 1991-1997 interval witnessed Multidisciplinary Design Optimization evolving into a tightly integrated framework that links optimization with multidisciplinary analysis through formal problem formulation, disciplined system decomposition, and enhanced cross-discipline communication. Research emphasized structured, scalable architectures and coarse-grained parallelism to enable collaboration across design domains, supporting systematic exploration of highly coupled design spaces. Early incorporation of evolutionary approaches addressed discrete and topology-driven decisions, while linearization and decomposition techniques improved tractability for mixed-variable problems within MDO contexts.