During that now seemingly innocent summer of 2001, Rich had been reading accounts of “civilian agonies” in Sarajevo, Baghdad, Bethlehem, Kabul — including Palestinian poet Mahmoud Darwish on the Beirut bombing of 1982. With every page, her unease grew.

“We here could not expect to feel invulnerable forever,” she remembers thinking. That thought became a catalyst for the poem crowning her new collection, “The School Among the Ruins: Poems 2000-2004.”

The volume has won this year’s National Book Critics Circle Award for Poetry.

Rich cited another catalyst for “The School Among the Ruins” in an e-mail interview from her Santa Cruz home — the school, in Brooklyn, where her son teaches.

“I knew his love for the school, for those children,” she said.

Set during a nonspecific wartime in which children and their teachers are hostages to horror, the poem includes these lines:

A morning breaks without bread or fresh-poured milk/

parents or lesson plans/

diarrhea first question of the day/

children shivering it’s September/

Second question: where is my mother?/

One: I don’t know where your mother/

is Two: I don’t know/

why they are trying to hurt us/

Three: or the latitude and longitude/

of their hatred Four: I don’t know if we/

hate them as much I think there’s more toilet paper/

in the supply closet I’m going to break it open

In choosing this as the title poem of her newest collection, Rich meant it “in a larger metaphoric sense — art as a school of the imagination in a world of violence and moral chaos.”

In making the poem, much work went into avoiding sentimentality, above all, and selecting “just enough” concrete detail; it went through many revisions.

Rich, 76, is known for her politically engaged work — passionate on the subjects of justice, civil rights and feminism. Over 40 years, she has published more than 20 books of poetry and essays. Her many awards include a MacArthur award, the Lannan Foundation Lifetime Achievement Award and a Bollingen Prize in American Poetry.

Accepting the National Book Critics Circle award March 18 in New York, Rich thanked “the movements and activists which have educated and fired me throughout my life.”

Thursday night in San Francisco, Rich will draw from “The School Among the Ruins” when she joins poet W.S. Merwin for a reading at the First Unitarian Universalist Center.

The event celebrates Merwin’s new collection, “Migrations: New & Selected Poems.” It also honors Rich and Merwin’s “old and continuing friendship in poetry,” she said.

Rich and Merwin met in Boston in the late ’50s, “probably through Robert Lowell,” she said.

Merwin’s first book had been published in the Yale Younger Poets series in 1954. The previous year, W.H. Auden had selected Rich’s first book for the same honor.

“I was living in Cambridge, married, with three small children. I’d go over on an afternoon and we’d talk about poems,” she said. “Both of us were going through changes in our work.”

They corresponded, sharing poems even while Merwin lived abroad. “Though we’d both taken part in various poetry readings against the Vietnam War,” she recalled, “I was increasingly involved with the political movements of the ’60s.”

It’s fitting, then, that Rich called her favorites of Merwin’s poems those from that era. She admires “a certain voice in them perhaps.” His poem, “Ash,” is “one of the most devastating, haunting poems I know, a wonderful example of what a political poem can be.”

The Thursday reading will benefit Merwin’s publisher, Copper Canyon Press — “one of the treasures of our culture of resistance,” said Rich.

So much of America’s great literature, especially poetry, has been published by small, independent presses, Rich marveled. “And we have two distinguished ones on the West Coast — Copper Canyon and City Lights.”