This Friday’s Chamber Symphony concert includes Beethoven’s Symphony No. 2. While perhaps not as well-known as his third, fifth, seventh, and ninth symphonies (all odd numbers!), the second is a masterpiece nevertheless. Indeed, if Beethoven had written only the second, fourth, and eighth symphonies (those least known at present), he would still be counted as one of the greatest of all symphonic composers.

With the Beethoven is a unique and wonderful work by the Swiss composer Frank Martin. Romantic in sensibility, the Petite Symphonie Concertante combines harp, piano, and harpsichord with strings for an unusual and gorgeous color. You will love it. Opening the program is Charles Ives’s “The Unanswered Question.” While some Ives is challenging – one audience member this year told me, “I think Ives is the Benjamin Britten of the U.S.!” – an in-joke for Festival devotees – this piece is intriguing, haunting, and accessible (Friday, July 19, 6 p.m. in the tent).

Saturday we present another unique program: four Bach keyboard concertos, one for one piano, one for two, one for three, and one for four (!) with an instrumental ensemble. Our distinguished piano faculty member Arie Vardi works with three wonderful recent piano students now making world-wide careers (Saturday, July 20, 8 p.m. in Harris Hall).

On Sunday we have yet another unique, unforgettable offering: An outdoor “installation” piece by visionary American composer John Luther Adams. The composer John Adams is also a visionary, but this is a different person. A few years ago, we presented John Luther Adams’s installation piece for 99 percussionists called “Inuksuit.” Hundreds were delighted by the surprisingly moving, absorbing, free music. This year, we have his work “Sila,” and it is sure to be a highlight as well (Sunday, free, 2 p.m. outside the tent). Then you can have some lemonade (not free), or set up your picnic and stay for the 4 p.m. concert.

Sunday’s orchestra concert will be an audience favorite. Leonard Slatkin, who had previously retired from summer festival tours, will be back, celebrating his 75th birthday. He has programed Elgar’s magnificent “Enigma” Variations and Rachmaninoff’s evergreen Piano Concerto No. 2. The soloist, making an Aspen debut, is Seong-Jin Cho, a laureate of Poland’s Chopin Competition.

Monday, we join with Theatre Aspen in our first ever collaboration together, presenting the All-American classic “South Pacific.” Rodgers and Hammerstein achieved one of their greatest successes with an adaptation of beloved James Michener stories. It’s a perfect choice for our “Being American” season (Monday, July 22, 7:30 p.m. in the tent).

Alan Fletcher is president and CEO of the Aspen Music Festival and School.