Structured Design. Edward Yourdon and Larry L. Constantine. Prentice-Hall, 1979.
This was one of the early structured “standard works” that I’ve only just gotten to for the first time. I’d learned things like coupling and cohesion, afferent and efferent flows, and the concept of factoring, but it’s much stronger coming directly from this source. Not everything here is compatible with the way I think about design, but this is one of those books that deserves repeated study.