AND THE MOUNTAINS ECHOED. By Khaled Hosseini. Riverhead Books. 404 pages. $28.95.

“And the Mountains Echoed” opens with an impoverished Afghan father telling his children, Abdullah and Pari a bedtime story, an engaging fairy tale that brings to mind the horrific opening scene in the film “Sophie’s Choice.”

The fairy tale features a div, which is a giant with curved horns sprouting from its head, an apparently heartless beast who randomly visited remote villages to carry off a child that had to be chosen by the parents. Otherwise, the div would carry off all the children in a given family. In essence, “a finger had to be cut, to save the hand.”

In Khaled Hosseini’s novel, the theme is carried, if not to a sweet ending, at least to a bittersweet one. Having already lost an infant son to the stresses of a severe winter, and facing another winter without the means to keep his family warm, the father agrees to sell Pari (5 or 6 years old) to a wealthy couple in Kabul. The sale allows the diminished family to survive, but the separation of Pari from them, especially from her brother, Abdullah, who is almost like a father figure to her, is wrenching. It makes for an emotional wound that eventually scabs over but never fully heals.

Having enjoyed immensely Hosseini’s first two novels, “The Kite Runner” and “A Thousand Spendid Suns,” I assumed I was in for another literary treat. Instead, it is an excruciatingly drawn-out, digressive “treatment.”

Readers who prefer novels more linear in construction and progression are likely to be frustrated by Hosseini’s latest. It skips chronologically as well as geographically. It jumps from fall 1952 to spring 1949 to spring 2003 to February 1974, etc., ad nauseam. It hops from the village of Shadbagh to Kabul and back numerous times, to Paris, to San Francisco, to Africa, to the Greek Island of Tinos, to California again, and finally to Avignon, France.

It must be allowed that sometimes digression can be used very effectively.

In the closing pages of “And the Mountains Echoed” (a title “inspired in part by William Blake’s poem, ‘Nurse’s Song’ ”), Hosseini, a physician, treats the subject of senile dementia with professional familiarity, literary skill and uncommon compassion.

Here, he describes what could be an adult daughter’s last visit with her stricken father: “I kissed his cheek again later when I rose to leave. I lingered my face against his, remembering how he used to pick me up from kindergarten.”

Reviewer Eugene Platt is a poet and senior commissioner of the James Island Public Service District.