Musician Donald Knaack, aka The Junkman, is celebrating his decades-long dance collaborations with Twyla Tharp, Ellen Sinopoli and more with a new compilation.

In 1976, record shoppers knew what they liked -- the Eagles and Rolling Stones, Stevie Wonder and Bob Dylan -- and they bought it in droves. Only 11 different albums reached No. 1 on the Billboard 200 ...