Scumbler, by William Wharton (Carroll & Graf, $3.95). According to one dictionary, to "scumble" is "to modify the effect of a painting by overlaying parts of it with a thin application of opaque or semi-opaque color." The scumbler of this novel is a 60-year-old expatriate American artist in Paris, a pacifist whose psychiatrist has accused him of being a psychopath. As he reminisces, the scumbler boasts of having lived his life largely as he pleased, admits to having "hurt a lot of people" in doing so, and explains his art as painting "the world the way I want it to be." Wharton is also the author of the much-praised Birdie.

A Buyer's Market, by Anthony Powell (Popular Library, $3.95). This, the second of the author's 12- novel work A Dance to the Music of Time, is typical of all the others in its baroque style, icy wit, and brilliant construction. The series' subject is the disintegration of the old British social order and the corresponding rise of the New Man, as epitomized by the deliciously odious bounder, Kenneth Widmerpool. The method is the most dextrous shuffling of characters since Trollope's Palliser novels. NONFICTION

Strategic Atlas: A Comparative Geopolitics of the World's Powers, by Gerard Chaliand and Jean- Pierre Rageau (Harper & Row, $14.95; hardcover $26.95). We have become accustomed to viewing the world horizontally as Mercator presented it centuries ago. From that perspective the Soviet Union seems far away, beyond the Atlantic, across Western and Eastern Europe. But the globe viewed from the North Pole shows the Soviet Union as our neighbor, almost connected to Alaska. With 224 multi-colored maps, Chaliand and Rageau shows our world from a variety of perspectives, each shift in view illuminating different geopolitical facts -- the oceans which covers 71 percent of the globe and where the strategic straits are located, the range of nuclear missiles, the world viewed from the Soviet Union and other countries, the different levels of wealth and population, energy and agricultural resources, where and to what extent nations expanded its boundaries in the past, the current zones of conflict. Recommended for military strategists, diplomats, and students of history and politics in both high school and college levels.

Weapons and Hope, by Freeman Dyson (Harper Colophon/Cornelia and Michael Bessie Book, $6.95). Part meditation, part reminiscence, part prescription, this look at wars and weapons is one of the few current "nuclear" books to place today's unimaginable threats in the context of history. Dyson reflects on why man acted as he did in past wars to predict his actions in the next. Unlike most doomsayers, Dyson believes we do have a reasonable chance of controlling our future. He is himself a distinguished physicist and long-time consultant to the Defense Department, which gives his perspective an impressive authority. He is also a wonderful writer, as already demonstrated in his autobiography, Disturbing the Universe. Weapons and Hope won the 1984 National Book Critics Circle award for nonfiction.

The Death and Life of Dith Pran, by Sydney H. Schanberg (Penguin, $4.95). In 1972 the author began reporting on Cambodia for The New York Times. In 1975 he was evacuated from Phnom Penh after its capture by the communist Khmer Rouge, leaving behind his Cambodian assistant, Dith Pran, who earlier had saved Schanberg's life. Four years later Dith Pran reappeared in a refugee camp on the Thai border, having survived what many people call the Cambodian Holocaust, in which an estimated 2 million of the nation's 5 million people were killed. Schanberg, now a Times columnist, won a Pulitzer Prize for his Cambodian reporting. His searing, life- affirming account of Dith Pran's disappearance and trek to freedom first appeared in 1980, and is the basis for the recent award-winning film, The Killing Fields. An epilogue brings Dith Pran's story up to date: he's reunited with his wife and children, working as a photographer and living in Brooklyn.

A Guidebook to Virginia's Historical Markers, compiled by Margaret T. Peters (University Press of Virginia, $8.95). One of the pleasures of the road in the Old Dominion is reading a historical marker that commemorates some flashing moment in the state's storied past. Sometimes, though, the car is traveling too fast to read the marker. This attractive guidebook remedies that problem, locating each marker geographically and reprinting its text. The effect is that of a painless lesson in American history, so much of which seems to have occurred within Virginia's boundaries. The markers started being placed in 1926, and they range from Marker No. KV-15 on Cape Henry -- "Near here the first permanent English settlers in North America first landed on American soil, April 26, 1607" -- to Marker No. K-1 in Lee County -- "Cumberland Gap. . . long the gateway to the West . . . Daniel Boone and numberless pioneers passed through it on the way to Kentucky."

The Shawnee Prophet, by R. David Edmunds (University of Nebraska Press, $7.95). After the American Revolution, white settlers poured into southern Ohio displacing the Indians in what came to be called the Old Northwest. The Indians of several tribes reacted violently to the seizure of their hunting grounds and under the leadership of Tecumseh and his brother Tenskwatawa -- the Shawnee Prophet -- formed a confederacy and fought a series of fierce frontier engagements against the fledgling U.S. Army before and during the War of 1812. Americans have tended to idealize Tecumseh as the Noble Savage, but in this brilliant revisionist history R. David Edmunds shows that it was the Shawnee Prophet who dominated the intertribal movement. The Prophet lived to have his portrait painted by George Catlin in 1832, in Kansas where the Shawnees had been sent after their defeat.

Unknown California, edited by Jonathan Eisen and David Fine with Kim Eisen (Collier/Macmillan, $10.95). Though the reason for the first word of the title is murky, this book is a handsome and comprehensive anthology of prose on the state that fires almost everyone's imagination. The pieces range from such old chestnuts as Mark Twain's "The Celebrated Jumping Frog of Calaveras County" to bulletins like the excerpt from The Mayor of Castro Street, Randy Shilts' biography of assassinated San Francisco supervisor Harvey Milk. There is also surprises: an article on the Watts section of Los Angeles by novelist Thomas Pynchon and a pre-Grapes of Wrath piece on migrant workers by John Steinbeck.