The subject categories are those used by most higher education libraries in the U.S. You must choose at least one category for the material being submitted. Select the category from the drop down menus and chick add to add the category to the list of categories appropriate for this material. You may add multiple categories if the material fits in more than one category from the list. This field is required. You may want to look through the entire list before you decide which categories best match the material you are submitting.