Very good quality, prime-period bootleg (some distortion, but otherwise, very solid for the era) of the Mothers, recorded by Don Preston from the stage, playing a set during their mid/late prime on a show that only recently surfaced.
"This superb set documents The Mothers Of Invention's appearance at the 1968 Schaefer Music Festival, sponsored by the Schaefer Brewing Company and held at the Wollman Skating Rink in New York City's Central Park. In exchange for $4,000 and what the contract described as "100% star billing," Zappa and his cohorts played two exhilarating 40-minute sets (at 8:00pm and 10:30pm), taking in early material, pieces that had yet to be recorded, and some that never would be."
"Part hip vaudeville and part musical inspiration... His arrangements were imaginative embellishments of full-blown ideas... Among the freshest things to be heard in jazz-rock."-The New York Times, August 1968