Books about C programming:

"The C Programming Language" by Brian W. Kernighan, Dennis Ritchie

"Programming in C" by Stephen Kochan

"C: A Reference Manual" by Samuel P. Harbison, Guy L. Steele

"C Traps and Pitfalls" by Andrew Koenig

"Expert C Programming" by Peter van der Linden

"Advanced Programming in the UNIX Environment" by W. Richard Stevens, Stephen A. Rago

"Unix Network Programming, Vol. 1: The Sockets Networking API" by W. Richard Stevens