Karlheinz Stockhausen is considered one of the most important composers of 20th century and is well regarded for his innovations in electronic music. He accomplished 370 total works during his prolific career as a composer which spanned almost sixty years. There's plenty of literature about Stockhausen and his music, and lots of information on the web. You can read about his interesting and often controversial life here.
Der Jahreslauf was composed on a commission from The National Theater in Tokyo in 1977. Originally, the piece was composed for Gagaku orchestra and dancers, but it is heard on this album performed by an orchestra with European instruments. The orchestra is comprised of three harmoniums, an anvil, three piccolos, bongos, three soprano saxophones, a bass drum, harpsichord and guitar. Taken from the notes:
"THE COURSE OF THE YEARS represents 4 musical time layers simultaneously: milleniums (3 harmoniums), centuries (anvil and 3 piccolos), decades (bongo and 3 soprano saxophones), and years (bass drum with harpsichord and guitar). Four temptations stop it, and each time an incitement starts it again. In concert performances, these temptations and incitements are heard as special events and words through loudspeakers."
I've included images of the notes in the download. Enjoy.