Among programming languages, SETL stands apart as the only one to have been designed to take advantage of the syntactic tradition of abstract mathematics. Schwartz's desire to free programmers from their preoccupation with machine-level concerns, and his recognition that people had already evolved notations which served as an aid to mathematical reasoning, combined to produce a language which to this day is unparalleled in its ability to express the most essential programming constructions concisely and naturally. It should perhaps come as no surprise that SETL gracefully handles the relatively mundane generalizations required in typical data processing. SETL is an elegant language, with clean semantics and a refreshing degree of orthogonality. The importance of these attributes to those who must deal daily with programs is profound. It is easy to take pride in one's work when the results tend to reward revisiting: a virtuous cycle of readability, robustness, and maintainability ensues.
SETL is a language which deserves to be taken seriously. I have tried to show in this dissertation how it excels in a realm remote from the algorithmic showpieces of 1970, how it can be really useful in the process-intensive age of the Internet, and what general principles and patterns seem to work best in this context. There is much work still to be done, but it is perhaps not too optimistic to hope that SETL's slow start will one day prove to have been a good start.