This report describes the concept of programming in a relational calculus. This is a style of programming in which entire relations are manipulated rather than individual data, and in which the program itself is represented as a relation. Thus relational programming is more general than functional programming in three respects. First, it is more general because relations subsume functions. Second, it is more general because the same objects, viz. relations are used to represent both the program and the data. Finally, since complex data structures are easily represented as relations, relational programming can manipulate with facility a much wider class of structures that other very-high-level languages. (Author)