"Initiative in Evolution" by Walter Kidd is a scientific treatise written in the early 20th century. The book explores the intriguing debates surrounding evolutionary theory, focusing on the roles of Lamarckism and Darwinism in the context of biological evolution. With numerous illustrations, it provides a detailed examination of how modifications in organisms might arise from both inherited traits and environmental responses. The opening of the text sets the stage for a rigorous exploration of evolutionary concepts by highlighting the historical context of biological inquiry, particularly following the Great War. It introduces the idea that the study of evolution involves questioning established doctrines and emphasizes a shift toward understanding how adaptations and changes may be transmitted across generations. Kidd proposes that examining the arrangement of mammalian hair serves as a key focal point, acting as a concrete example of how environmental factors may influence evolution and how these effects could potentially align with neo-Lamarckian principles. (This is an automatically generated summary.)