The original OpenStep design documents are at NextComputers.org. The Programming Reference, UI Guidelines, and Specification continue to apply to GNUstep. The hypothetical Desktop is similar to GWorkspace. The Development Tools, and Porting advice are universal concepts.
Sun Microsystems: (September 1996)
OpenStep Programming Reference 802-2112
OpenStep User Interface Guidelines 802-2109
Quick Start to Using the OpenStep Desktop 802-2101
Using the OpenStep Desktop 802-2102
(For details about Edit.app, IconBuilder.app, ProjectBuilder.app, and expected Unix paths):
OpenStep Development Tools 802-2110
Porting NEXTSTEP Applications to OpenStep on Solaris 802-2115
NeXT Computer: (October 1994)
OpenStep Specification 19941019
There are some minor differences between OpenStep 1994 and 1996. I am interested in the original design reconstructed from these two versions before Apple bought NeXT. By contrast, GNUstep policy legacy supports Apple extensions for compatibility sake.
-- John