4.4BSD is the final release of what may be one of the most significant research projects in the history of computing. When Bell Labs originally released UNIX source code to the R&D community, brilliant researchers wrote their own software and added it to UNIX in a spree of creative anarchy that hasn't been equaled since. The Berkeley Software Distribution became the repository of much of that work.
One outcome of UNIX's distributed authorship was an approach (the UNIX "man pages") that allows individual software contributors to use a standard format for documenting the software they've written. Though sometimes criticized as too terse, now that extended third party tutorials are widely available, this approach starts to look like a brilliant strategy. Nothing beats the ease of lookup of an alphabetical listing. For all their faults, the UNIX "man pages" are among the most useful and widely used documentation for any system!
This volume collects the man pages for the various UNIX programming libraries, plus related information for programmers. It consists of sections two through five of the online man page collection:
(2) UNIX System Calls (3) C Library Subroutines (4) Special Files (device interfaces) (5) File Formats
The information in this volume is useful not just for 4.4BSD systems, but also for many related UNIX implementations, including SunOS, BSDI, and Linux.