You can organize frequently used procedures into modules you store in
libraries — workbooks that contain only modules — and make these procedures visible throughout a program without having to copy them into every module or workbook that calls them. You can make the procedures in a library workbook visible to procedures in another workbook by creating a reference from the workbook that contains the calling procedure to the library workbook. For more information about creating a reference to a library workbook, see "Creating a Reference to a Workbook" later in this chapter.
After you've created a reference to the library workbook, procedures in other workbooks can call procedures stored in the library workbook. For more information about calling procedures in other modules and workbooks, see "Calling Procedures in Other Modules" later in this chapter.