Every writer has a theme. Or, better yet: Every good writer has a theme -- a driving idea that focuses conviction, spurs imagination, gives force to words. For Camus it was loneliness; for Tolstoy it was the tide of a churning world; for Austen it was the subtle ways a society forges individuals. For Adam Hochschild it is the division between Haves and Have-nots.

Hochschild grew up a child of privilege with a keen eye for observation. His worldview took on a new perspective in the summer of 1962 when, at 19, he went to Capetown, South Africa, to work for an anti-apartheid magazine. "It was the first time in my life," he says, "that I realized that for some people in this world, politics is serious business. It is not dinner-table amusement. It is something that could put you in prison. The people I worked with in Capetown were in jail more often than they were not. A man I knew there was hanged. I came back a changed person."

He was born in Manhattan in 1942, the only son in a well-to-do family. His father was an executive with an American company that mined copper in Africa. Theirs was the good life, filled with all the comforts money can buy. But at 18, Hochschild accompanied his father on a business trip to North Rhodesia. "I realized then that all I'd done, everything I'd had was dependent indirectly on the labor of Africans." It was the seed of his lifelong theme.

The family moved to Princeton in 1950, and some years later Hochschild was sent away to the Pomfret School, where that theme was refined further. "I began to see the sharp outline of a class structure. The teachers were almost entirely people who had struggled through life, worked their way through college, been educated on the GI Bill. They were acutely aware of the differences between them and the kids. The teachers were there to serve; and the kids took their privilege for granted. I couldn't help noticing that."

He was at Harvard when American troops began trickling into Vietnam, and he did "what children of means did in those days": He dodged the draft by joining the U.S. Army reserves and working construction, building latrines. The reserves were never tapped for combat. In 1964, he spent the summer in Vicksburg, Miss., reporting for a black community newspaper in the heat of the civil rights struggle. Thereafter, on a lark, he traveled to California, where he has remained ever since.

He was hired as a reporter for the San Francisco Chronicle but two years later left to write and edit for Ramparts magazine, a hub of liberal intellectuals. In 1968, he dropped out of Ramparts to write "the Great American Novel," but when it was rejected by a string of publishers, he returned to magazine work. "At the time I felt a huge felony had been committed against American literature," he says, "but later I realized that in many ways the novel had been a draft for my memoir."

In the mid-1970s, Hochschild and a number of his colleagues founded Mother Jones, a progressive magazine pitched at the general readership. He concentrated on editing, a career he feels greatly improved his writing. "Editing demystifies words. You become businesslike about judgments. How many words is an idea worth? How much space in a magazine? Would a picture tell the story better? What does the reader want? When I went back to writing, I was more mature about it. Words weren't so sacred any more."

In 1986, he produced his first book, Half the Way Home, a memoir that described his difficult relationship with his powerful father. In 1990, he published The Mirror at Midnight: A South African Journey, in which he plumbed the questions of apartheid. Four years after that, he wrote The Unquiet Ghost: Russians Remember Stalin, for which he traveled to the farthest reaches of the former USSR, searching out mass graves and asking Russians how it could be that the country that gave us Pushkin could also be the one that gave us the gulags. Last year, he published King Leopold's Ghost, about the atrocities committed in the Belgian Congo at the turn of the last century.

The theme of injustice runs like a clear lode through Hochschild's work. Little wonder that he looks for that motif in everything, scanning footnotes for clues to what he might write next. "Subjects don't come easily," he says, "and I always live in a limbo when I am in between. Writing a book is like falling in love. You have to be obsessed to do it well." He may not know the particulars of his next project, but we can assume a few things about its general contours. There will be Haves. They will have a monstrous sense of entitlement. Their power will careen out of control. And the mayhem will break your heart.