Every little movement / Has a meaning all its own." On one level, Maude Maggart is a creature of pure intellect—the overarching conceit of her new show is the metaphor of American culture as a garden, superimposes the flowers (the Great American Songbook of the 20th century) against the soil and the roots (the vaudeville and minstrel songs of the 19th century). Yes, from a distance it sounds more like a Ph.D. thesis than a nightclub act. But then, Ms. Maggart is the most emotional and vulnerable singer you're likely to experience anywhere. When she builds to the show's climactic ballads (Kern and Hammerstein's "Can I Forget You?") she creates the illusion of being completely exposed, the illusion of not having any illusion. Throughout, she has you thinking that she's completely traditional and old-fashioned, while actually being a cutting-edge radical all the while.

You've never heard anybody begin a show like this: Ms. Maggart starts with a collage of passages from various songs, but the show is nearly over before you realize that she has somehow mashed up the introductory verses to four tunes and created something entirely new out of them.

In showing how the modern Songbook grew out of the allegedly less-sophisticated songs of earlier generations, Ms. Maggart is consistently deconstructing numbers and re-assembling them. After leaving us hanging with that sequence of verses, she returns to the choruses to nearly all of those songs later in the show.

The first number that she does all the way through is Noel Coward's "Where Are the Songs We Sung?" At first it seems like a quixotic choice, but it becomes clear soon enough that she's focusing on numbers from the 1920s and 1930s that look nostalgically backward, like Coward's plea for those innocent airs, "When the love in our hearts was young," and Irving Berlin's 1922 entreaty, "I am yearning / to be returning / Back to those crinoline days." She contradicts this with the same Berlin's "Pack Up Your Sins," which depicts a jazz-age cabaret-speakeasy as a kind of dancing Dante's Inferno with a satanic DJ-bandleader at the center. Like Berlin, Ms. Maggart often is at her most innocent when she's reveling in the deliciousness of sin, and her most archly perverse when trumpeting the praises of earlier and supposedly simpler times.

Conversely, Ms. Maggart makes the oldest songs seem the most relevant to today: the century-old antique "Your Daddy Did the Same Thing 50 Years Ago" includes the prescient line, "He looked into your mother's eyes / Told an awful lot of lies / And that's why you're here today." Likewise, George M. Cohan's 1904 "Life's a Funny Proposition After All" could be a lead-in to Bob Dylan's cautionary tale regarding the inevitability of being stoned. The most emphatic life lesson comes from the oldest text, the pre-Christian words of Ecclesiastes in "Turn! Turn! Turn!"

Along the way, she celebrates the careers of forgotten artists like Marie Lloyd, who somehow in the tightly corsetted Victorian age specialized in saucy songs of scintillation, and the Hutchinson family, who used the music of the minstrel show to spread the word of abolitionism. Meanwhile, the garden metaphor is another ball that she keeps in the air, from Ivor Novello's "We'll Gather Lilacs" to Ned Washington's description of "Mother Earth's green" in "100 Years From Today." Yet neither her scholarship nor her juggling act outpaces her sincerity as a performer: When Ms. Maggart begins singing, she instantaneously, right before our eyes, teleports herself back to the era and into the heart of the song. She's being it rather than merely talking about it.