This book uses the history of cell theory to explore the emergence of biology as a distinct field in its own right--separate from anatomy, physiology, and natural history. It also explores nineteenth- and twentieth-century ideas about heredity and development and the progress that was made at the turn of the century when they began to be studied on their own--leading to new understandings of a variety of biological problems, from evolution to cancer. Investigating this story will help readers gain an appreciation of the historical development of scientific ideas. It beautifully illustrates that the process of science is not as straightforward as it is usually portrayed. One of the important lessons of this intriguing story is that "facts" do not necessarily speak for themselves, and observations always need to be interpreted.