This text includes an overview of the scope of the design of the TSQL2 temporal query language, a listing of the design goals for the language and a brief introduction to the major concepts of the language. It also presents a detailed examination of each of the language's major design decisions, discussing alternatives and surveying previous approaches, and a detailing of the changes that would be necessary to augment a conventional, non-temporal data base management system (DBMS) to support the facilities of TSQL2. The book also contains the language specification itself, as an upward compatible extension of SQL-92.