American female vocal soul sister-trio formed in 1968, Chicago. They released their two first albums at , produced by Isaac Hayes and David Porter. They switched to in the mid 70's. Their association with Earth, Wind & Fire's Maurice White brought them at the top of the charts with "Best Of My Love". They had big success as well with "Boogie Wonderland" sang with Earth, Wind & Fire. They released ten albums between 1971 - 1985.