Pizza is a lot of things to a lot of people. Mostly, though, it's just food. Colin Atrophy Hagendorf is keenly aware of both sides of this not-quite-burning issue in his debut book, Slice Harvester. Subtitled "A Memoir in Pizza," it chronicles a two-year period in Hagendorf's life, from 2009 to 2011, when the 20-something burrito deliveryman wrote a blog called Slice Harvester, in which he reviewed a plain slice of pizza from every pizzeria in Manhattan. Hundreds of them.