It was an astounding discovery in the early 1980's that the same genetic sequence, the homeobox, controlled the development of basic body plans across the animal kingdom, whether the result was a flatworm, an octopus, a mouse, or a human. This discovery of the conservation of a key developmental mechanism across phyla and vast stretches of evolutionary time helped launch the interdisciplinary field of evolutionary developmental biology, or Evo-Devo. In Evolution and Development: Conceptual issues (Cambridge University Press, 2024), Alan Love explains and explores Evo-Devo and the philosophical problems that arise in its pursuit. Love, who is professor of philosophy at the University of Minnesota-Twin Cities, considers such issues as the type of scientific unity that arises from focusing on problem agendas rather than theory, the problem of determining when variation in traits gives rise to a novel trait, and how the identity of features at various levels of biological organization can be explained by particular causal mechanisms.