The outstanding concert at the Kennedy Center Friday night by the St. Louis Symphony Orchestra under Leonard Slatkin was the final preview of the music the group will perform on a month-long European tour that began yesterday.

It marks the ensemble's first comprehensive tour of the continent -- yet another landmark in the St. Louis Symphony's development, spurred by the orchestra's quantum leap to the top rung of American orchestras in six years under the prodigiously gifted Slatkin. It is one of the major musical success stories of this generation.

The St. Louis does not yet match the sheer virtuosity of Chicago or Boston, but it produces a solid, warm sound -- beautifully blended. Each choir is rich and full, yet without the giddy high frequencies that lend excitement, but sometimes stridency as well, to, say, the New York Philharmonic.

There is, further, an even more important trait of the St. Louis Symphony. It never seems to play anything indifferently -- merely going through the motions the way even the greatest ensembles sometimes play. There is no doubt that this is considerably due to their conductor.

Now only 40, Slatkin is one of those rare musicians who always direct themselves more to mastering the substance of the music than merely to mastering the notes themselves. He seems to immerse himself in the music, seeming less concerned with putting his particular stamp on a piece than with seeking out the work's own special stylistic stamp.

For example, Friday night's performance of Leonard Bernstein's "choreographic essay" "Facsimile" fairly bristled with hard-edged rhythmic drive and complexity, especially in the eruption of symphonic jazz in the third of the four sections. Slatkin's conducting brought to mind the dazzling rhythmic precision that Bernstein the conductor is so famous for (Slatkin's podium manner, in fact, recalls Bernstein's in many ways -- the jumps in the air to get a really emphatic accent, the unusually wide but lucid beat, the agonized facial expressions).

Heroic lyricism was what Slatkin was after in the Liszt Second Concerto, with pianist Misha Dichter. It was played like a tone poem for piano and orchestra, its romantic ebb and flow superbly meshed between conductor and soloist. Dichter achieved some amazing technical feats at the keyboard, but they were always subordinated to the overall conception.

In Sibelius' huge Second Symphony, Slatkin emphasized the tender side of the work -- eliminating the bloated quality and the exhausting sieges of hysteria heard in so many interpretations.