Long before the hydrogen bomb indelibly associated radioactivity with death, many chemists, physicists, botanists, and geneticists were excited thinking that radium held the key to the secret of life. Luis Campos examines the many and varied connections between early radioactivity research and understandings of vitality, both scientific and popular, in the first half of the twentieth century. As some physicists and chemists early on described the wondrous new element and its radioactive brethren in lifelike terms ( decay, half-life, and frequent reference to the natural selection and evolution of the elements), many biologists of the period eagerly sought to bring radium into the biological fold. They did so with experiments aimed at elucidating some of the most basic phenomena of life, including metabolism and mutation, and often saw in these phenomena properties that in turn reminded them of the new element. These initially provocative links between radium and life proved remarkably productive in experimental terms and ultimately led to key biological insights into the origin of life, the nature of mutation, and the structure of the gene. "Radium and the Secret of Life" traces the half-life of this connection between the living and the radioactive, while also exploring the approach to history that emerges when one follows a trail of associations that, asymptotically, never quite disappears."