Books/Info on UNIX Network Questions

[Bob Drotleff]

	Hi,
		Can someone give me information on a good book(s)
		for understanding/using/implementing communications
		between UNIX systems and other systems whether they be
		UNIX or otherwise.
		Basically, I'm trying to understand data communications
		in UNIX terms i.e. sockets, cu etc. or anything.     
		Any help is greatly appreciated.
		Please Email me with any info.

		Thanx again.