| Book | Covers | License | |------|--------|---------| | Modern C (Jens Gustedt) | C11, C17, C23 | CC-BY-SA | | C Programming: A Modern Approach (K.N. King) – 2nd Ed | C99/C11 | Commercial, but excellent | | The C Book (Banahan et al.) | C90/ANSI C | Free online (legacy) | | Beej’s Guide to C Programming | C11/C17 | Free/Public domain |

If you want "modern C" (C11, C17, C23), you don't want K&R. You want "C Programming: A Modern Approach" by K. N. King (often called the "King C book"). This is effectively the unofficial 3rd edition that everyone is looking for. It covers C99 and C11 in detail.

No legal free PDF exists. You can: