A system enabling an application programmer to construct a plurality of application programs for communicating with a plurality of remote machines of a plurality of machine types, each of the plurality of remote machines having remotely accessible data and remotely performable operations includes a computer system with a memory, a processor, and a mass storage device, the computer system for storing programs, class declarations, and class libraries in an object-oriented programming language, means for compiling files containing source-code representations of application programs in the object-oriented programming language, implementations of a hierarchy of data description classes, each implementation for describing a set of data and for describing methods for manipulating the set of data, implementations of a hierarchy of remote data description classes, each implementation for describing data items contained in one of the plurality of remote machines and for describing methods for accessing the data items, and source code files for a plurality of sample application programs, each sample application program for communicating with at least one of the plurality of remote machines.