Wick 4: One Word of Truth (WICK series)
Although W1CK is in many ways a prequel, it is absolutely a stand-alone novel.  It does take place 20 years before the events of The Last Pilgrims, and in the same universe... and the W1CKstories are designed to define and illuminate what led up to the post-apocalyptic story that unfolds in TLP, but W1CK can be read on its own--as a story about a man who looks at his world and what it means to be free.  The entire WICK series is now available, and a WICK Omnibus Edition will be available on August 10th of 2013.