I uploaded PDFs of the original V7 UNIX manuals into the Doc Management tab. These are fascinating historical documents containing lots of information from the beginnings of UNIX. Download and take a look!
Volume 1 is the usual man set - commands, libraries, API, file formats, etc.
Volume 2a is detailed info about various subsystems and UNIX in general
Volume 2b is more subsystems (yacc, lex, and much more)
-Tom