Susan Sontag was known for her essays, where she often embraced ideas and art that were considered "difficult." Her essays can be intimidating, so I am going to suggest an entry point for those who have not read them before.
Regarding the Pain of Others is a fairly recent book, and one which should be of interest to nearly everyone. It is in fact very timely, because it deals with the topics of war and human suffering.
Regarding the Pain of Others is in some ways an update on views expressed in Sontag's earlier award-winning book, On Photography. Regarding the Pain of Others however, is not a book about art, as her previous book was. It is about our endless exposure to scenes of horror, disaster, pain, war and torture through the medium of photography.
In the past week, I have spoken with many friends about how difficult it is to comprehend the tsunami disaster in Asia. We see the images on television, one picture of terrible loss after another, until the mind goes numb. We do not want to look, yet we can't stop looking. Sontag writes about such images of suffering with great fervor and sensitivity, drawing on many tragic events in recent history that will be familiar to the average reader.
Regarding the Pain of Others struggles to understand what it means to bear witness to horrible things that are happening to other people--whether the events are accidents of nature, like the tsunami, or inflicted by others, as in war.