Amazon shows books through #14, "Begin Again", published Sept '03. The blurb on Amazon indicates that it is the final book: "The end of the world has come and gone, leaving only ruins, and the Remnants. This is the final chapter in their saga. The Remnants, Marauders, and Alphas are being summoned by the Source. Unsure of the future, and weary from the past, the group travels. But not everyone trusts the power and promise of the Source. Can it truly bring life back to planet Earth? Will the Remnants survive to tell the tale of the Rock--the times before and the times after? Only the Source knows if the universe will end, or begin again. All will be revealed."

I watched a movie based on the story.