This is largely a matter of personal preference and may be dependent on how many people are working with the EndNote libraries and how organized you are. The EndNote producers recommend that users keep all their references together in one main or master EndNote library. This usually avoids hassles inherent in splitting references between libraries and then needing to have multiple libraries open in order to create a bibliography for one paper. Using multiple libraries can also become problematic if a number of people are working on the same project. Instead of making different specialty libraries, you will probably find it more useful to create one library and use the Groups function to help you organize and categorize your references. Using the Groups function will enable you to quickly move selected references to a specific group of references and navigate between groups of references.