Immersed in time-weathered musical materials, demonstrating a near-absolute mastery of the pop song craft that has been crystallizing at the conjunction of blues and country for half a century, Williams' writing is excellent only when it isn't superlative. Her lyrics are easeful, trenchant, imaginative, concrete and waste free, her tunes always right there and often inescapable. There isn't a duff song on the three records.

Yet beyond print media, where she's lionized whenever she sticks her head out of her lair, Lucinda Williams can hardly catch a break. She gets covered in Nashville and even won a songwriting Grammy after Mary-Chapin Carpenter cut the tongue out of "Passionate Kisses," and if Lucinda Williams maintains its steady sales pace, it will go gold around 2038. Smitten bizzers keep giving her advances, too. But she has never charted, and her labels have a terrible way of vaporizing. Say a little prayer that Mercury rides out the latest upheavals at Polygram.

Car Wheels on a Gravel Road, the album that Mercury bought from American Recordings' Rick Rubin (who mixed all but one track), was a legendary six years in the making. Williams is such a perfectionist that she recorded it from scratch twice and then folded in more guest solos and recut vocals than even long-suffering co-producer Roy Bittan could fully digest – always with the perverse goal of making it sound less produced. And, astoundingly, that's what has happened. Not only is Car Wheels on a Gravel Road more perfect than the two albums that preceded it, which English grammar declares an impossibility, but it achieves its perfection by being more imperfect.

Dubious instrumental add-ons are crucial to this strategy: Gurf Morlix's acoustic slide guitar on "Jackson," Bittan's wisps of accordion on "2 Kool 2 Be 4-Gotten," Greg Leisz's blues mandolin on "Concrete and Barbed Wire." But the illusion of casualness is most palpable in the singing. Williams' big voice has always thrived on contained emotion – soul strengthened by its refusal of overkill. But not since the openhearted Happy Woman Blues has she gotten so much feeling on tape. This she accomplishes without belting – although the music rocks like guitar-bass-drums-plus should, she's never as loud or fast as someone dumber might be. She skillfully deploys the usual roughness tricks, from sandpaper shadings to full-scale