I would suggest one of the following:
1) Take a C programming course at a university. Being able to bounce questions off an instructor and other peers is a good way to go. And, depending on the quality of the instructor, you might get far more insight than you would from just reading a book.
2) "C Programming Language" by Kernighan and Ritchie. http://www.amazon.com/Programming-La.../dp/0131103628
Actually, #2 might end up being your textbook for #1.