Recherches sur les substances radioactives is a groundbreaking scientific treatise authored by Marie Curie, first published in 1904. This seminal work documents Curie's pioneering research into the phenomenon of radioactivity, a term she herself coined. Drawing from her meticulous experiments, Curie details the discovery and isolation of the elements polonium and radium, both of which she identified in collaboration with her husband, Pierre Curie. The book systematically explores the properties, behaviors, and measurement techniques of radioactive substances, offering comprehensive data and analysis that laid the foundation for the field of nuclear physics. Curie's narrative is both methodical and insightful, providing in-depth descriptions of experimental apparatus, chemical procedures, and the challenges faced in isolating minute quantities of radioactive materials. She discusses the spontaneous emission of energy from certain elements, the effects of radiation on photographic plates and living tissue, and the implications of these findings for the broader understanding of atomic structure. The work also includes detailed tables, observations, and theoretical interpretations that reflect Curie's rigorous scientific approach. Recherches sur les substances radioactives is not only a testament to Marie Curie's intellect and perseverance but also a milestone in the history of science. It captures the excitement and transformative potential of early radioactivity research, influencing generations of physicists and chemists. The book remains a vital reference for those interested in the origins of nuclear science, the development of modern chemistry, and the remarkable achievements of one of history's most celebrated scientists.