Abstract: A computer-human interface employs parts as the basic structural elements of documents. At the time a part is opened, an editor is bound to the part in a manner which makes most efficient use of programs available on the computer. The binding system first determines whether the preferred editor for the part is available on the computer. If so, that editor is bound to the part and launched, if it is not already running. If the preferred editor is not available, the system attempts to locate the most suitable handler for the part, based upon various characteristics of the part's contents, such as their category and kind. If a suitable editor or other handler is available on the computer, it is bound to the part and launched. If necessary, the part is translated from one kind into another kind for which an editor is available. If no editor suitable for the part can be located within the computer's available programs, a handler of last resort is bound to the part as its editor.