I think you could make the case -- depending upon how you measure these things - that "Walls of Time" is the greatest bluegrass song anybody has ever written. I mention this because Peter Rowan composed it with bluegrass patriarch Bill Monroe when Rowan was a Bluegrass Boy in the 1960s. Even if you know the song, there's a good chance you don't know Rowan had a hand in its creation. According to Monroe's biographer Richard D. Smith, "Peter had to keep reminding Bill that he deserved co-writing credit." The dark, death-haunted "Walls" is the consummate fusion of two sensibilities, Monroe's formed by old-time Southern ballads, Rowan's by Romantic poetry. Once heard, it is not forgotten.

Monroe died in 1996, but Rowan, a fixture on the folk and bluegrass scene since the early '60s, continues, currently with this affirmation of the grandness of the bluegrass tradition as carried by such historic figures as Bobby Osborne, Jesse McReynolds, J.D. Crowe and Del McCoury, who appear behind Rowan on The Old School. All but one of the songs (the stirring slave-era spiritual "O Freedom") are Rowan's, either his own or in collaboration, and performed in a distinctive style that owes a debt to Monroe but very much on Rowan's own terms.

It's not quite all bluegrass. One of several highlights is "Doc Watson Morning," a tribute to the departed master, joined by Bryan Sutton, among the leading acoustic-roots guitarists of his generation. Just as Watson was not a bluegrass musician (if often misidentified as one), Rowan's song -- composed with Jerry Faires -- is not bluegrass but a warm reminiscence set to Watson-inspired flat-picking, with references to classic songs and tunes associated with him, not least one of his exceedingly rare originals, the sadly apposite death-hymn "Your Long Journey."

Besides "Watson Morning" The Old School features three striking songs which only Rowan could have written. "Ragged Old Dream" remarkably echoes, without quite imitating, Jimmie Rodgers, demonstrating how Rowan is able to wear his influences on his sleeve while expressing a distinctly personal, heartfelt art. The same can be said of "Letter from Beyond," almost an answer to "Walls of Time," only communicated from the other side. Notwithstanding a title that might lead you to expect treacle, "True Love to Last" is a beautiful and wise song that no young writer could have conceived.

Only the overblown "Mountain Man's Dream," which sets its ambitions high and fails to reach them, stumbles. Over all, though, School serves to remind those who have followed his music of Rowan's stalwart, special gift.