Cream was a mathematical impossibility: the sum of the parts was greater than the whole. The inherent conceit of the band's name trumpeted the wedding of Britain's hottest guitarist, Eric Clapton, to a powerhouse rhythm section of Jack Bruce, whose inspired, creative bass playing reflected his jazz background, and Ginger Baker, whose tuneful, relentless drumming quickly became the model for numerous followers. Experimental in the studio, improvisational on stage, Cream had a short life span, but it was a brilliant one.Or was it? The band's first album, Fresh Cream, contained no classic songs but, led by covers of "Spoonful, " "From Four until Late," and "I'm So Glad," it featured several very good ones as it established Cream's blues bona fides. The follow-up. Disraeli Gears, channeled the blues power into the pop hits "Strange Brew" and "Sunshine of Your Love," flashed psychedelic with "SWLABR&qu ot; and "Tales of Brave Ulysses," and rounded it out with strong filler. But while one half of Wheels of Fire had some great studio tracks ["White Room," "Politicia n," "Deserted Cities of the Heart," and covers of "Sitting on Top of the World" and "Born under a Bad Sign"], the other half sank with overlong, indulgent live tracks save for sterling "Crossroad s"