This standard is intended for use by all those who want to write portable message-passing programs in Fortran and C (and access the C bindings from C++). This includes individual application programmers, developers of software designed to run on parallel machines, and creators of environments and tools. In order to be attractive to this wide audience, the standard must provide a simple, easy-to-use interface for the basic user while not semantically precluding the high-performance message-passing operations available on advanced machines.