Differentiation, the stepwise specialization of cells, and transdifferentiation, the apparent switching of one cell type into another, capture much of the stem cell spotlight. But dedifferentiation, the developmental reversal of a cell before it reinvents itself, is an important process, too. This loss of specialization is believed to factor heavily into stem-cell culture techniques and pathological conditions such as cancer. Determining its programming, however, or even definitively identifying the process defies best efforts and flies in the face of Occam's razor: Here, the simplest explanations hardly seem sufficient.