K&R gets so much hell, but it's a good, raw back to basics text. It deserves a place on the shelf beside the ARRL Ham Radio License Manual, or Wheelock's Latin, or Lyman's Guide to Reloading, or The Joy of Cooking, or the Elements of Style. It's the programming book for Boy Scouts, a crude, but essential Swiss Army Knife --the great programming book for the post-Apocalypse.
Also all of these are open source submissions.