Albert Einstein and J. Robert Oppenheimer, two iconic scientists of the twentieth century, belonged to different generations, with the boundary marked by the advent of quantum mechanics. By exploring how these men differed—in their worldview, in their work, and in their day—this book provides powerful insights into the lives of two critical figures and into the scientific culture of their times. In Einstein’s and Oppenheimer’s philosophical and ethical positions, their views of nuclear weapons, their ethnic and cultural commitments, their opinions on the unification of physics, even the role of Buddhist detachment in their thinking, the book traces the broader issues that have shaped science and the world.

Einstein is invariably seen as a lone and singular genius, while Oppenheimer is generally viewed in a particular scientific, political, and historical context. Silvan Schweber considers the circumstances behind this perception, in Einstein’s coherent and consistent self-image, and its relation to his singular vision of the world, and in Oppenheimer’s contrasting lack of certainty and related non-belief in a unitary, ultimate theory. Of greater importance, perhaps, is the role that timing and chance seem to have played in the two scientists’ contrasting characters and accomplishments—with Einstein’s having the advantage of maturing at a propitious time for theoretical physics, when the Newtonian framework was showing weaknesses.

Bringing to light little-examined aspects of these lives, Schweber expands our understanding of two great figures of twentieth-century physics—but also our sense of what such greatness means, in personal, scientific, and cultural terms.

On the fiftieth anniversary of Hiroshima, Nobel-winning physicist Hans Bethe called on his fellow scientists to stop working on weapons of mass destruction. What drove Bethe, the head of Theoretical Physics at Los Alamos during the Manhattan Project, to renounce the weaponry he had once worked so tirelessly to create? That is one of the questions answered by Nuclear Forces, a riveting biography of Bethe’s early life and development as both a scientist and a man of principle.

As Silvan Schweber follows Bethe from his childhood in Germany, to laboratories in Italy and England, and on to Cornell University, he shows how these differing environments were reflected in the kind of physics Bethe produced. Many of the young quantum physicists in the 1930s, including Bethe, had Jewish roots, and Schweber considers how Liberal Judaism in Germany helps explain their remarkable contributions. A portrait emerges of a man whose strategy for staying on top of a deeply hierarchical field was to tackle only those problems he knew he could solve.

Bethe’s emotional maturation was shaped by his father and by two women of Jewish background: his overly possessive mother and his wife, who would later serve as an ethical touchstone during the turbulent years he spent designing nuclear bombs. Situating Bethe in the context of the various communities where he worked, Schweber provides a full picture of prewar developments in physics that changed the modern world, and of a scientist shaped by the unprecedented moral dilemmas those developments in turn created.