The Dirty Dozen Brass Band first attracted attention as a bit of a novelty, a New Orleans street parade band that incorporated modern jazz and R&B without stringed instruments. They have since evolved into one of the best jazz bands of any description, and last night at the damp Fort Dupont Summer Theater, their solos were models of dramatic shape and sensual tone. The same thoughtfulness went into their unison work, which resembled a disciplined big-band horn section as much as a Mardi Gras parade.

Fortunately, their sense of playfulness was intact, and they opened Professor Longhair's "Going to New Orleans" with a three-part whistling harmony that led to parade-chant vocals and hot jazz trumpet solos. Yet the band also filled Horace Silver's bop standard "Song for My Father" with lush ensemble harmonies and fluid, fiery sax solos by Kevin Harris, the band's most improved player, and Roger Lewis.

Singer MaryAnn Myles opened the show with a polished set of crossover pop-soul tunes. Backed by an able funk quintet and a smooth harmony vocal quartet, Myles displayed a big, appealing voice and good gospel improvisational instincts, but she hasn't yet found the distinctive persona to separate her from the rest of the crowded pop-soul field.

Myles and the Dirty Dozen Brass Band return to Fort Dupont tonight.

Peter, Paul & Mary

Some performers need no introduction, and Peter, Paul & Mary received none at Wolf Trap Thursday night. They simply trotted on stage to applause and began singing "No Easy Walk to Freedom," the best song from their latest album. When the crowd joined them in singing the next tune, "Where Have All the Flowers Gone?" you could almost feel time spinning backward.

Was the show nostalgic? How could it not be? But it was also whimsical, inspirational, political, a bit corny and, at times, revealing (as when Mary Travers confessed to having a Republican for a son).

Over the course of two sets, the trio and bassist Dick Kniss encountered momentary lulls, notably a couple of tired ballads by John Denver and Gordon Lightfoot. Far better were original numbers like Noel Paul Stookey's "El Salvador," which has to be one of the most incisive and tuneful songs ever written about the subject. However, for sheer energy and crowd approval, nothing rivaled the rousing sing-along versions of "Blowin' in the Wind" and "This Land Is Your Land."