Brief History of Z39.50 Evolution
Pre-1979: The context for the standards work
1979: Formation of Z39 Subcommittee D on Computer-to- Computer Protocols
1981: SC D decision to review rather than write protocol specifications
1984: Failed ballot on draft standard
1985-88: Preparing draft standard
1988: Approval of Z39.50-1988
1990: NISO establishes Z39.50 Maintenance Agency
1990: Organizational meeting of Z39.50 Implementors Group (ZIG)
1992: Approval of Z39.50-1992 (Version 2)
1992: Z39.50 Interoperability Testbed
1995: Approval of Z39.50-1995 (Version 2 & 3)