This paper contains an axiomatic theory of first order modal logic with operations, identity, and descriptions together with a formal semantics which interprets the theory in such a manner that empty universes of discourse and denotationless terms are allowed for at each possible world. The intuitive basis of the theory is discussed in preliminary sections, the syntax and semantics of theory are then characterized, its semantical adequacy is demonstrated, and certain important axioms and theorems are discussed in detail in later (...) sections. (shrink)