FOUCAULT'S PENDULUM by Umberto Eco (Ballantine: $6.95). Three writers labor over a labyrinthine tale that ends in a cosmic joke.
THE CHINCHILLA FARM by Judith Freeman (Vantage: $9.95). Verna Fields sorts out the conflicts of her Utah Mormon upbringing on her way to L.A.
AVON BOOKS PRESENTS CHRISTMAS ROMANCE by Catherin Hart, Betina Krahn, Linda Ladd, Barbara Dawson-Smith, Katherine Sutcliffe (Avon: 4.50). Various places, periods and people weather the Yule-tide season in these five stories.
MYSTERY by Peter Straub (Signet: $5.95). A young boy of 10 and his aging neighbor pair up to solve a 40-year-old murder in their quaint Caribbean town.
AND THE WALLS CAME TUMBLING DOWN by the Rev. Ralph David Abernathy (HarperPerennial: $12.95). Abernathy, a foot soldier in the march for civil rights, casts a disparaging light on one of its captains, Martin Luther King Jr.
AMERICAN FAMILY STYLE by Mary Randolph Carter (Viking Studio: $18.95). Four seasons in a Virginia family's home decorating, cooking, gardening and entertaining traditions.
WITHOUT MERCY: Obsession and Murder Under the Influence by Gary Provost (Pocket: $4.95). True-crime chronicle raises some thought-provoking questions: Are alcohol and blinding love extenuating circumstances in a murder? Is the person executed after years of appeals the same person who commits the crime?
AN OLD MAN'S TOY: Gravity at Work and Play in Einstein's Universe by A. Zee (Collier: $9.95). Theoretical physicist suggests Einsten's idea is all relative.