Marginal decisions to increase the net of revenue minus costs arise in non-profit organizations as much as in companies. The designers of a recent book, Peter Leeson‘s The Invisible Hook (Princeton University Press, 2009), recognized this in picking a cover. The dust jacket features a wooden background (a plank?), onto which a transparent hook has been laminated – thus a semi-visible hook! Pretty cute, but the lamination adds to total variable cost. So why do it? Presumably the Press believes that this design will make the book stand out from others and sell more copies. Total revenue will rise, perhaps by more than the increase in variable cost. If so, this was a wise business decision; if not, at least it’s an innovation that will help make the Press more visible in the publishing world.