As one who's been listening to bluegrass most of his life, I never cease to marvel at the genre's durability, its way of both reinventing and reaffirming tradition while holding an audience just big enough to keep its practitioners, if not in wealth, at least in business. As a style, bluegrass (which dates from the latter 1940s) is not exactly ancient, but it distantly echoes the sound of 19th-century rural string bands, as filtered through jazz, blues, Southern hymns and spirituals, 1950s country music and the 1960s folk revival. For all practical purposes it is the invention of Bill Monroe (1911-1996), truly a benefactor to humanity.

Doyle Lawson is one of the half dozen or so giants of current bluegrass. Lonely Street celebrates 30 years of recordings -- 34 of them, if I'm not mistaken -- under his own name and that of his band Quicksilver, with its ever-shifting, usually young personnel, for whom their time with Lawson is something like boot camp, in all senses. A considerable number of those albums are gospel-themed, and they represent that genre, integral to bluegrass since its inception, at its most intense and affecting. Hardly surprisingly so -- Lawson's records are best known for their magnificent harmony singing, and most bluegrass gospel is harmony-based.

Gospel songs -- two of them, both excellent -- appear on Lonely Street, but otherwise the songs are rooted in the secular themes of country (Lawson's knowledge of the trad-country repertoire has always been close to encyclopedic) and, of course, bluegrass. Proceedings kick off with "Monroe's Mandolin," a deeply felt tribute to the master, written by Virginia and Vernon Long, whose opening notes some listeners will recognize as a quote from Monroe's stirring instrumental "My Last Days on Earth." Buddy Cannon and Michael Wayne Smotherman's "My Real World of Make Believe" recalls the sound and sentiment you'd hear wailing from any jukebox in any low-down dive in small-town America 50 years ago.

Throughout, Lawson shares lead vocals with guitarist Darren Beachley, while both find their places in harmony with bassist Carl White. (Lawson sings both baritone and low tenor.) I've never heard the title song, an often-covered country-pop tune, sung entirely in three-part harmony, or its melody pushed to something a tad more sprightly and bluegrass-appropriate, but as both idea and execution, it's an inspired choice.

On the other side of the generational gap is Spring Creek, a Lyons, Colorado, band embarking on what will surely be, if it stays together ("if" always the qualifier in such matters), a notable career. Spring Creek is a four-member outfit, most of them (if I may judge from the photographs) not far past their 20s. Most, too, hail from Texas, where bluegrass is not unknown but where younger roots-oriented musicians are more likely to be drawn to honkytonk, Townes Van Zandt-style folk, electric blues or neo-rockabilly. A couple of highly regarded musicians, fiddler Michael Cleveland and resophonic guitarist Sally Van Meter, put in welcome appearances.

For the most part Way Up on a Mountain draws on original material, in-the-tradition stuff, sturdy and prepared to stand up to the challenge of repeated listening. Particularly winning are bassist Jessica Smith's occasional lead vocals, calling up the ghosts of legendary, long-gone hillbilly singers like Molly O'Day, Wilma Lee Cooper and Rose Maddox. Banjoist Chris Elliott's exhilarating instrumental "Cuba Vera Swing" pretty much defines joyful noise as picked in the stringband section of hillbilly heaven.