The book begins with a thorough introduction to Darwin's early life, detailing his upbringing in Shrewsbury, England, and his education at Edinburgh University and Cambridge. Francis Darwin paints a portrait of his father as a curious and observant child, whose early interests in nature foreshadowed his future contributions to science. The narrative captures the influences of family, friends, and mentors who shaped Darwin's thinking, highlighting his evolving fascination with natural history.

A significant portion of this volume is dedicated to Darwin's correspondence, which includes letters exchanged with fellow scientists, naturalists, and family members. These letters not only reveal Darwin's thoughts on various scientific topics but also his reflections on personal matters, his relationships, and the societal implications of his work. Readers gain insight into his meticulous research methods, the challenges he faced in developing his theories, and the impact of his ideas on the scientific community and society at large.