Abstract: A Multi-Level Architecture for developing intelligent computer systems composes computational modules uniformly across diverse developmental framework. The modules interact via message passing and are assembled to form application-specific systems. A first level of the Multi-Level Architecture includes a cooperative operating system which provides support for message passing and resource allocation and is preferably based on a module-oriented programming (MOP) model. The first level, for example, defines a virtual machine which is mapped onto an underlying hardware and operating system environment. A second level of the Multi-Level Architecture supports a plurality of application-independent problem-solving frameworks (PSF's) or programming environments for building modules and combining modules of different frameworks into complex systems.