We describe a binding of the XDR protocol to the Common LISP programming language and the binding's routine's library implementation. The implementation solves compatibility problems arising in the exchange of structured data between modules coded in different programming languages and/or hosted by computing environments with different hardware architectures. Our facility is used for module interconnection within ABE, an environment for the development of distributed, heterogeneous systems, which is briefly described. Our XDR binding to LISP radically differs from other bindings previously proposed in that we use an explicit association mechanism from XDR types to LISP types, which contributes the several important characteristics of the implementation, and might be adopted for bindings to other languages. Complex application programs are easier to write and can efficiently overcome the assumption that a module must know in advance the type of a datum it is going to receive. Our binding retains full compatibility with other XDR bindings, e.g. to C and LISP, with increased power, flexibility, and simplicity of use.