The Database Relational Model: A Retrospective Review and Analysis
C.J. Dateis an author, lecturer, researcher, and independent consultant specializing in relational database systems.  An active member of the database community for almost 30 years, C. J. Date devotes the major part of his career to exploring, expanding, and expounding the theory and practice of relational technology.  He enjoys a reputation second to none for his ability to explain complex technical material in a clear and understandable fashion.