Barbara Kingsolver jokes that whenever she publishes a novel she apparently turns into a railway station because, according to reviewers, ``I only do departures.''

But while all of Kingsolver's books reflect a shimmering set of sensibilities, her latest novel stands a bit apart from her beloved debut The Bean Trees, its sequel Pigs in Heaven and other humorous and heartbreaking female-driven works about family and identity. The Lacuna (Harper, $26.99), which Kingsolver will discuss Monday at Miami Book Fair International, deals with those themes, too. But it delves even deeper into politics and national identity.

Set in the early-to-mid 20th century in Mexico and the United States, it's narrated by Harrison William Shepherd, a necessarily closeted gay writer who, as a youth, works in the households of Diego Rivera, Frida Kahlo and ``Lev'' Trotsky.

The Lacuna isn't exactly Kingsolver's first historical novel. The spellbinding The Poisonwood Bible -- about an evangelical missionary and his family -- was set in the Congo in 1959, before independence. But The Lacuna's wider historical sprawl proved trickier to pin down.

``The Poisonwood Bible required a lot of research, but this was 40 times more,'' Kingsolver says from her Virginia home. ``It stretches across 30 years. Every new day in this novel required another month or two of research. That's why it took seven years.''

COMPLEX ISSUE

Kingsolver says she was lured to the subject matter by a long-held passion for studying the complex relationship between art and politics.

``It fascinates me that countries have different attitudes toward artists, in terms of what we want to hear from them,'' she says. ``Many countries look to artists as bellwethers of the political and moral climate of their times. Mexico notably celebrates its most political artists as national heroes. In the United States we're uneasy with dissident art. I don't want to say we don't allow it. We do. But there's a kind of skepticism of political art that's unique to this country. . . . What makes us uneasy?''

Kingsolver has dipped into hot-button issues before. In her nonfiction Animal, Vegetable, Miracle, she writes about her family's year of eating only local or home-grown food. A character in the novel Animal Dreams fights for social justice in Nicaragua. And Prodigal Summer tackles biology, farming and the respecting and honoring of the natural world.

She ``inspired me to write about things that make a difference,'' says novelist A. Manette Ansay, professor in the University of Miami's M.F.A. creative writing program and author, most recently, of Good Things I Wish You. ``I heard her speak while I was in graduate school at Cornell University. She read from The Bean Trees and also from a book of nonfiction, Holding the Line, about the role of women in the 1983 Arizona mine strike. Her passion was so unapologetically straightforward and plainspoken that it really cheered me up. I was new to academia at the time, developing something of the cynical patina that is often confused with intellectualism, and she was so smart and fresh and bright she really set me straight.''

Questions reflected in The Lacuna -- the enigmatic title refers first to a gap in a rocky shoreline and then to the hole, the mysterious part, that lurks in every story -- began to arise after 9/11.