The WU Libraries Catalog supports non-Latin text, however, many records are only searchable in Latin characters according to the American Library Association- Library of Congress Arabic romanization tables. Diacritics are not necessary for catalog searches.
Subject heading searches will be in English, and can be limited to Language-> Arabic in Advanced Search.
It is not necessary to include Al- at the beginning the "last" or "family" name of an author search, unless:
If an author commonly publishes in English, they will be searchable by the name as spelled on those publications.
Al- is always spelled with "L" regardless if the following letter is a sun or moon letter.
Library of Congress subject headings are used across several catalogs, including WU Libraries, HathiTrust, and Worldcat. Use subject searches in combination with keywords and language limiters (see the Books tab for example searches) in multiple catalogs for best results.