Adaptationist Evo-Devo is a practical and inviting guide to one of biology's most vital ongoing conversations: how to explain the diversity of life by connecting natural selection to the developmental processes that make evolution possible. Without calling for a revolution or declaring anything broken, Olson gently maps out an expansive way forward, one grounded in mutual regard for the different ways biologists approach the problem of form. Rather than dividing the field into theoretical camps, the book shows how combining the strengths of population biology, comparative biology, developmental analysis, optimality modeling, and physiology leads to clearer questions and better-supported explanations. For anyone unsure how to link variation, heritability, fitness, and possibility into a coherent picture, this book celebrates the common ground, shared interests, and collaborative potential across evolutionary biology and ecology. Through vivid examples, from humble goldfish to radish flowers and butterflies to scaling laws, it shows how to move from assumption to evidence, how to navigate tricky ideas like "constraint" and plasticity, how to manage biological metaphors and to sidestep the traps of false dichotomies. Rather than a winner between "adaptation" and "development," the book offers a shared toolkit that quietly dissolves the need for choosing sides.Adaptationist Evo-Devo makes the case that evolutionary biology works best when its practitioners listen across subfields, and it offers a common language to help them do exactly that.