Chicago is busy these days (the band, not the city) and it's not surprising.

This year marks the group's silver anniversary. In 1967 six young musicians with varied backgrounds - rock, classical and jazz - gathered at a dining room table in the Windy City and plotted a new era for rock. Theirs was to be a band in which the horn section was a major part of - not just an adjunct to - the sound.Two years later, Chicago Transit Authority debuted with its first album. With the second album release, the name of the group was shortened to Chicago, and the distinctive sound was solidified with such memorable hits as "Make Me Smile," "Beginnings" and "25 Or 6 To 4."

Other groups had success with the heavy brass sound. Blood, Sweat and Tears and Tower of Power are two examples. But only Chicago has lasted a quarter century with its stature undiminished, having sold more than 100 million albums worldwide. It enjoys the distinction of having had hit singles in four different decades, from the '60s to the '90s.

Always a big draw in Utah, Chicago will appear at ParkWest Friday, July 17, at 7 p.m. The stop here is part of a major tour of North America that began May 22 and has included such venues as New York and Detroit. Throughout June, the band was a co-headliner with the Moody Blues, but is finishing out the summer on its own.

Honored May 4 with its own star on Hollywood Boulevard's Walk of Fame, Chicago was the subject of a recent documentary on ABC's "In Concert" for two consecutive weeks. Chicago plans to record a new album in September.

The band has not survived without personnel changes. Today's lineup consists of Jason Scheff (bass, vocals), Walt Parazaider (woodwinds), James Pankow (trombone), Lee Loughnane (trumpet), Robert Lamm (keyboards, vocals), Bill Champlin (keyboards, guitar, vocals), Dawayne Bailey (guitar) and Tris Imboden (drums).

Scheff, who replaced Peter Cetera in 1985, is a competent bass player and gifted tenor whose vocals are nearly indistinguishable from Cetera's on the older tunes.