This book is a thought-provoking assessment of assumptions inhibiting progress in comparative biology. The volume is inspired by a list generated years earlier by Donn Rosen, one of the most influential, innovative and productive comparative biologists of the latter 20th century. His list has assumed almost legendary status among comparative evolutionary biologists. Surprisingly many of the obstructing assumptions implicated by Rosen remain relevant today. Any comparative biologist hoping to avoid such assumptions in their own research will benefit from this introspective volume.