While I'm certainly good at C, and have been the guy people asked the C and C toolchain questions at a couple places I've worked, I'd say you're in for more than 1 book to grok the topics you've expressed interest in, and haven't met the single book that does all you want.

1: If you're a python programmer, I do suggest staying with pure C and AWAY from C++. You have little use case for it if you can mix python and C and it is literally pain incarnate while you do not know every little bit of it and/or work with people who do not know every little bit of it.

2: Secondly, a single book on C will not get you where you're going. You will need several.

3: I'd stick with K&R for reference, but then go to the following two books for threading and all the other stuff like networking:

You need these two books to get down C and it's ecosystem (make, autotools, etc): Advanced Unix Programming by Rochkind (Really good explanation of signals especially): http://www.amazon.com/Advanced-UNIX-Programming-Marc-Rochkin...

Gnu/Linux Application Programming by M. Tim Jones (Recovers some of the same stuff as AUP, but does better with the toolchain): http://www.amazon.com/GNU-Linux-Application-Programming/dp/1...

If you want to go more advanced, this is likely the correct book: Advanced Programming in the Unix Environment: http://www.amazon.com/Advanced-Programming-UNIX-Environment-...

Although if you're diving deep into networking, this is likely the correct book: Unix Networking Programming: Vol I by Stevens:

http://www.amazon.com/Unix-Network-Programming-Sockets-Netwo...