A four-part album series housing more than two hours of music and two dozen songs inspired by an ancient Persian poem? With an accompanying film for each section - and in 2022, when they say nobody cares about long-players anymore? That's chutzpah. But it's also entirely in character for the Tedeschi Trucks Band.

Susan Tedeschi and Derek Trucks demonstrated their chutzpah back in 2010 when they formed the 12-member collective modeled in the grand organic tradition of the Allman Brothers Band (which Trucks, nephew of their late drummer Butch Trucks, played in from 1999-2014), Grateful Dead, the Band, Leon Russell's Hello People and others of that ilk. They haven't wavered from the path throughout four previous studio albums, but with I Am the Moon they're doubling down on that creative ambition, knocking down any walls that may still be standing before them. It's challenging, for sure. But the group's combination of musical excellence and daring won't be denied, which makes I Am the Moon, in all of its unapologetically indulgent grandeur, a career-defining work.

The project offers an epic musical interpretation of "Layla & Majnun," a 12th-century poem by Nizami Ganjavi that was also source material for Derek and the Dominos' "Layla." (Trucks has toured with Eric Clapton, and the TTB released a live rendition of Layla and Other Assorted Love Songs on last year's Layla: Revisited (Live at Lockin'). I Am the Moon dips even deeper into the poem's 90 pages to explore themes of interpersonal relationships (romantic and otherwise), faith, longing and searching for higher ground. The first batch of music on I Am the Moon I. Crescent, follows suit, with meticulously crafted arrangements and exchanges that are still loose enough to feel like beatific improvisations.

The five-track Crescent is, at 36 minutes, the second-longest of I Am the Moon's four parts, each designed to impact like a self-contained album from the original vinyl heyday. The opening "Here My Dear" sets the tone, with a soulful groove that trickles into Tedeschi's vocal melody (and nods to the Marvin Gaye song and album of the same name), with Trucks and keyboardist Gabe Dixon trading fills alongside. The brass is gentle, and the song builds and swells as if the musicians are feeling their way into the pocket.

The Mike Mattison-sung "Fall In" is a playful New Orleans second-line marching song, with Trucks’ National Steel slide ringing through it, while "I Am the Moon" boasts a soaring, elegiac feel a la Bob Dylan's "Knockin' on Heaven's Door." "Circles 'Round the Sun" finds Tedeschi in a troubled, questioning mode ("Tell me what has love earned?") as guitar and brass stab in and out of the arrangement, leading to a gleefully formless jam that ushers the track to its end. Then there are the 12-plus minutes of "Pasaquan," an epic within an epic and the only instrumental piece in the I Am the Moon project. Named after a folk compound in Georgia near the Trucks' home, it sprawls through swamp rock, free jazz (including a drum solo) and psychedelia, a kitchen sink of sound that yields new sounds and textures with successive listens. Even in its short running time, Crescent is a rich immersion and a gauntlet of sorts, giving the listener a lot to buy into - and an indication of how much more lies ahead. It certainly requires an investment of time and attention, but here's betting that the effort will be rewarded with a summer of sweeping musical adventure.

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