abbreviation for Professional Auditor's Bulletin: one of a series of issues written by L. Ron Hubbard between 10 May 1953 and 15 May 1959. The content of these bulletins is technical and promotional. Their intent was to give the professional auditor and his preclears the best possible processes and processing available at the moment it became available. —ExDn Lectures Approved Glossary: Illness Breakthrough (7 April 1972)