Unix Time-Sharing System Programmer's Manual, Seventh Edition (1983), Vol. 1 & 2

Design & Implementation of the FreeBSD OS, 2nd Ed

The Linux Programming Interface: A Linux and UNIX System Programming Hardcover

Windows System Programming (Addison-Wesley Microsoft Technology Series)

The Design and Implementation of the FreeBSD Operating System

Unix Shell Programming (3rd Edition)

Lot of 10 Computer Science Books on Networks

Essential SCO System Administration Keith Vann For Unix & Open Desktop Servers