O’Reilly Media book: 21st Century C

21st Century C:
If you know how to program with a general purpose language such as Ruby or Python, you can also learn how to use the C language in a practical and modern style. However, you need many techniques that are entirely absent from every C textbook on the market—except this one. 21st Century C assembles all the tools you need to write efficient, state-of-the-art programs with C.