At the End of All Our Labors by Potassium Cockburn $13. 284 pages. ISBN-13: 978-0692506165 • ISBN-10: 0692506160 September 2015 The central character in Potassium Cockburn’s novel has a job to do, and several successive layers of reality in which to do it, but it’s not clear who he’s really working for, or that the