There are many stunning moments on “Lost and Safe,” the latest set of electro-acoustic concoctions by the Books, but one passage particularly crystallizes the duo’s singular approach. Halfway through “An Animated Description of Mr. Maps,” a sampled voice describes a “soft-spoken loner,” and percussion sneakily mimics every syllable, until speech and rhythm become one.

Through three hypnotic albums, the duo of Nick Zammuto and Paul de Jong has blurred the line between words and music. Mixing vocal samples with acoustic instruments and computer processing, the pair finds music in speech, words in notes, and a million possibilities in between. The group’s name is fitting: The Books’s songs are constructed more like sentences and paragraphs than measures and melodies. And last year’s “Lost and Safe” (Tomlab) is equally well-titled, so full of new ideas it sounds foreign, yet so gently tuneful as to be immediately comfortable.

The Books formed in 2000 when de Jong, a classically trained cellist from the Netherlands, met Zammuto, a Boston-born guitarist and sound artist. They were living in the same apartment building in Manhattan and bonded over a mutual love of audio archiving: De Jong had built a trove of samples from old records and films, while Zammuto collected field recordings and interviews for his sound sculptures.

On their 2002 debut, “Thought for Food” (completed in the basement of a North Carolina bed and breakfast), the Books established a method of songcraft using vocal samples as building blocks. Around these snippets, Zammuto and de Jong wrapped acoustic melodies and odd-sounding rhythms, often made from guitar and cello recordings chopped up by computer editing.

Constructions like the gently looping “Read, Eat, Sleep” and the echoing “Contempt” (based on bites from the Jean-Luc Godard film of the same name) use samples to communicate rather than decorate. Where much sample-based music can feel like a flashy Hollywood blockbuster, Zammuto and de Jong’s work is more like the subtle visual poetry of director Michel Gondry, using effects as textures to enhance ideas, not tricks to wow an audience.

After the release of “Thought for Food,” Zammuto moved back to Massachusetts, where he set up the studio that he and de Jong (who still lives in New York) have used ever since.

In 2003 the Books released “The Lemon of Pink,” extending previous ideas into more expansive sonic territory. The hypnotic folk of “Don’t Even Sing About It” and the aching yearn of “S Is for Everysing” moved Zammuto’s delicate guitar and de Jong’s creaky cello closer to the foreground, while the country-ish title track married banjo to the shivering vocals of guest Anne Doerner.

On “Lost and Safe,” Zammuto’s own voice is as prominent as those that he and de Jong sample. His whispered singing evokes the quiet hooks of bands like American Analog Set and Yo La Tengo, where previous albums melded the sound-bite ingenuity of Negativland with the pastoral folk of John Fahey.

Still, the Books continue to mine unexpected sources. On “It Never Changes To Stop,” a preacher-like voice implores an audience to sit still to the sad strains of bowed cello. Later, “Vogt Dig for Klopperlok” builds rhythm from footsteps on pinecones, and the beat of the aforementioned “Mr. Maps” comes from a bleating subwoofer locked inside a filing cabinet. Even Zammuto’s lyrics have unpre dictable origins: “Twelve Fold Chains,” an intensely quiet ballad, is based on a 2,500-year old Buddhist text.

The careful work that goes into the Books’s music (Zammuto and de Jong do everything themselves, from writing and recording to mixing and mastering) has made playing live a challenge.They rarely did so until last year, when they added Doerner and Zammuto’s brother Mikey on bass to tour as a quartet. De Jong’s massive video collection helped the transition. Many of the movies he samples on record provide visual accompaniment for the band’s live sounds.

Multimedia performance seems to be just the next step in Zammuto and de Jong’s evolving oeuvre. Having perfected their unique sound in only three albums, they could easily choose to tread water and wait for the rest of us to catch up. But in the Books’s fertile music, change is likely to remain the only constant.

The Books will perform on May 5 at Northsix (66 N. 6th Street, Brooklyn, 718-599-5103) and on May 24 at the World Financial Center’s courtyard gallery (200 Liberty Street, 212-945-2600).