Abductive Inference: Computation, Philosophy, Technology(edited by John and Susan Josephson) is a collection of chapters by the Josephsons and their colleagues at Ohio State University’s (OSU) Laboratory for Artificial Intelligence Research. It describes six generations of abducting machines and a decade of related research. While other researchers make substantial contributions (a table lists 24 contributors), the editors participate in each chapter to an extent far greater than in a conventional anthology. This unusual structure does not work out to the benefit of the reader, as we will see later.