One of the distinguishing features of modern life is that it supplies countless opportunities for regarding (at a distance, through the medium of photography) horrors taking place throughout the world. Images of atrocities have become, via the little screens of the television and the computer, something of a commonplace. But are viewers inured - or incited - to violence by the depiction of cruelty? Is the viewer's perception of reality eroded by the daily barrage of such images? What does it mean to care about the sufferings of people in faraway zones of conflict?

Susan Sontag's now classic book On Photography defined the terms of this debate twenty-five years ago. Her new book is a profound rethinking of the intersection of "news," art, and understanding in the contemporary depiction of war and disaster. She makes a fresh appraisal of the arguments about how pictures can inspire dissent, foster violence, or create apathy, evoking a long history of the representation of the pain of others - from Goya's The Disasters of War to photographic documents of the American Civil War, lynchings of blacks in the South, the First World War, the Spanish Civil War, the Nazi death camps, and contemporary images from Bosnia, Sierra Leone, Rwanda, Israel and Palestine, and New York City on September 11, 2001.

This is also a book about how war itself is waged (and understood) in our time, replete with vivid historical examples and a variety of arguments advanced from some unexpected literary sources. Plato, Leonardo da Vinci, Edmund Burke, Wordsworth, Baudelaire, and Virginia Woolf all figure in this passionate reflection on the modern understanding of violence and atrocity. It includes as well a stinging attack on the provincialism of media pundits who denigrate the reality of war, and a political understanding of conflict, with glib talk about a new, worldwide "society of spectacle."