Mac OS 9

From Applepedia

MacOS 9 

What should have been 8.7 became 9 as to make sure no other versions would come out before OS X. Added CarbonLib, Multiple Users, AppleTalk over IP.

MacOS 9.1 

Bugfixes and stuff.

MacOS 9.2 

Improved Classic compatibility, removed support for PowerPC 601, 603, and 604 CPUs.

List of Mac OS versions

Classic Mac OS: System 1-5, System 6, System 7, Mac OS 8, Mac OS 9

Mac OS X: Mac OS X 10.0 (Cheetah), Mac OS X 10.1 (Puma), Mac OS X 10.2 (Jaguar), Mac OS X 10.3 (Panther), Mac OS X 10.4 (Tiger), Mac OS X 10.5 (Leopard)