One of several reasons for the overwhelming public rejection of contemporary classical music is its sterility, a lack of genuine emotion or, at the very least, a seemingly universal inability to express any depth of emotion effectively. One exception on the local scene is the music of Joan Tower, whose heartfelt piece “In Memory” was spotlighted during an interesting Thursday evening at the Morgan Library featuring the Chamber Ensemble of the Orchestra of St. Luke’s.

While Anton Bruckner was composing his Symphony No. 7, his idol, Richard Wagner, died. Bruckner immediately rethought his plan for the Adagio, changing the character of the entire composition to a funerary one. While Ms. Tower was writing her string quartet — there is also a full string orchestra version — in memory of a friend who had recently passed, the events of September 11, 2001, happened and, as she shared with the audience in a few introductory remarks, quite a lot of anger welled up within. The resulting work is devastatingly rich in emotion and almost painful to experience.

The quartet (Krista Bennion Feeney and Eriko Sato, violins, Louise Schulman, viola, and Myron Lutzke, cello) threw themselves into this agonizing writing with complete abandon. It was endearing to observe Ms. Schulman’s foot stomping as she emphasized a particular accent or harsh dissonance. The piece occasionally recalls Threnody for the Victims of Hiroshima by Krzysztof Penderecki and sometimes a Bernard Herrmann film score, but always conveys intensity and a harmonic language suffused with empathy and honesty. It is hard to imagine a more invested reading than this one by the St. Luke’s players.

The concert was titled “Four, Five, Six” and therefore included a string quintet. Considering all of the great examples in the literature — Schubert, Mozart, Brahms, Dvorák — it was a strange choice to perform the youthful A Major Quintet of Felix Mendelssohn (Brahms was out because his Sextet No. 1 closed the program). Truth be told, it is not much of a piece, but the selection turned out to be apposite and demonstrated St. Luke’s scholarly side.

The original score of the Mendelssohn is owned by the Morgan and was displayed under glass in the lobby. It was thrilling to peruse this document constructed in such a fanatically meticulous handwriting. Mendelssohn was an amateur artist of considerable talent, a sketcher of remarkably detailed exteriors, and his written handiwork is stunningly uniform and clear, perfectly constructed augenmusik. The sharply defined performance by the quintet, with Mr. Lutzke sitting out and violist Ronald Carbone and cellist Daire FitzGerald joining in, was an apt reflection of the printed pages.

Further, Mendelssohn completed the quintet when he was 17 but did not see fit to publish it straightaway. When his mentor Eduard Rietz died, Felix jettisoned the original Menuetto and replaced it in a shuffled order of movements with a eulogy in sound that he labeled Intermezzo, and writing, in what would for this evening’s purposes become a fitting parallel to Ms. Tower’s work, the inscription “Nachruf” (“In Memory”). Not only did the performers offer the published quintet, but also presented separately the rejected movement contained in the library’s original manuscript. Even for a rare work, this was a rare treatment and it was much appreciated. I daresay Mendelssohn experts have had little opportunity to experience this now forgotten movement in concert, and any of them in attendance this night heard it intoned in a delicate and loving manner.

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Classical musicians always want to be someone else. Pianists wish to conduct, singers to direct. Orchestral musicians yearn to be chamber musicians or soloists. Conductors dream of releasing their inner composer. At Avery Fisher Hall on Friday evening, the American Symphony Orchestra presented works by four such maestros with four very different stories.

George Szell made a remarkable triple debut in Berlin at the age of 13 as pianist, conductor, and composer with the Philharmonic. Already an accomplished touring pianist, he had been dubbed by the British press “the new Mozart.” Judging by his Variations on an Original Theme, written at the age of 16, which opened Leon Botstein’s program, he was well on his way to a prolific and productive career. The fact that he chose instead to become arguably the greatest conductor of the 20th century does not diminish his potential as a creative artist.

The work is especially impressive in its maturity and its facility in counterpoint, variation technique, and subtle use of orchestral color. Certainly Mozart was nowhere near this level of mastery at 16, although may have been just a tad more capable of melodic invention. Szell’s vocabulary is decidedly Straussian, the unmistakable sound of Till Eulenspiegel cavorting around the stage.

The orchestra sounded brilliant, nimble and lush by turns. These variations put an ensemble through many stylistic paces, and the musicians responded in an elastic manner. The length of the piece made it an ideal curtain raiser, but its natural charm also made it by far the most interesting offering on the menu. The rest of the evening turned out to be a bit of a chore.

Paul Kletzki’s Violin Concerto is a Romantic ramble on the order of the perfumed but forward looking pieces that grew out of the fin de siècle. I thought of Alexander Zemlinsky in spots. Soloist Robert Davidovici performed yeoman service and navigated his rather longwinded part, wherein there are sometimes an awful lot of notes in a short space of linear time, with great surety. The orchestra was fine as accompanists, but often their parts seemed almost superfluous, like those in the two Chopin piano concertos.

Harold Farberman is a drummer who grew up in New York and apparently took inspiration for his Double Concerto for Violin and Percussion from the sounds of jackhammers outside of his window early in the morning. I had moved to the back of the hall prior to this arbitrary and ultimately silly piece, and was glad that I did. Oddly for a work featuring the struck instruments, the exercise was preponderantly arrhythmic, really just a lot of random noise. Did lead percussionist Simon Boyar play his part accurately? Who knows? Who cares?

The program concluded with the Symphony No. 2 of Leonard Bernstein, but you already know his story.