Edward Nash Yourdon was an American software engineer, computer consultant, author and lecturer, and software engineering methodology pioneer. He was one of the lead developers of the structured analysis techniques of the 1970s and a co-developer of both the Yourdon/Whitehead method for object-oriented analysis/design in the late 1980s and the Coad/Yourdon methodology for object-oriented analysis/design in the 1990s.

In software engineering, structured analysis (SA) and structured design (SD) are methods for analyzing business requirements and developing specifications for converting practices into computer programs, hardware configurations, and related manual procedures.