I think there are better (more correctly written) guides to network programming, i.e., UNIX Network Programming (old, but the newest volume: The Sockets Networking API - was written in 2003), and TCP/IP Illustrated (also most recently updated with a 2nd edition in 2011) by the late, great W. Richard Stevens - despite his sole work being horribly out of date, with later volumes being worked on by Bill Fenner and Andy Rudoff, I would honestly look no further in lieu of socket programming in C.
More formal and comprehensive, absolutely. If you want something that's more friendly to neophytes, Beej's guide is the way to go. It's quite literally what they used in my upper div intro to Networking course at UCLA years ago.
A book that splits the difference very well is The Linux Programming Interface by Kerrisk. When I did network programming in class I leaned on it at least as much as Stevens.
It's a great book for all kinds of stuff, too, not just network programming.
