Set in Southern California and Iraq, it tells the story of Zach, a young and naive military photographer who stumbles upon a secret network of underground water pipes ("horizontal wells") in Iraq used to smuggle what are apparently scrolls containing the original prosperity Gospel, an interview with Jesus peddling free market doctrine.

Umo, about the same age as Zach, is an unschooled homeless illegal immigrant odd-jobber from somewhere in China or Mongolia who seems to know everything important.

Cannonball is one of the most realistic and pleasurably challenging depictions of the protean world and ever-reconfiguring mind that I’ve read ... McElroy uses contemporary surfaces to entice us into an epistemology, a “calculus cure” for reductionism .... McElroy forces the reader to work in order to highlight his belief that knowledge is not a given ..., in the hope that Cannonball might be — in the words of one of his soldiers — a “weapon of mass instruction”.

More than simply psychological realism or political critique, Cannonball is a significant artistic achievement—a brilliant novel of consciousness and conscience.

Laudable for its brio alone, Cannonball marries adolescent fumbling to Orwellian nightmare, while developing a deliciously wicked fantasy out of our country's Iraq misadventure.