Talk to The Elephant:

With its varying short-lived phases, King Crimson is well suited to the box set treatment, and overall, Frame by Frame: The Essential King Crimson doesn't disappoint. At four discs, it's perhaps a little hefty to serve as a comprehensive introduction for newcomers, even though it could work very well in that context; in the end, the box is more of a close-to-definitive package for fans who fall somewhere in between the realms of casual and devoted. The first three discs do an excellent job of summarizing King Crimson's extremely distinct prime-period lineups: the first disc concentrates on the often jazzy symphonic rock of 1969-1971 (including almost the entirety of In the Court of the Crimson King), the second covers the heavy, experimental soundscapes of 1973-1974, and the third features the off-kilter, new wave-influenced prog pop of 1981-1984. The fourth disc is a career-spanning sampler of live Crimson, and although the varying sound quality and musical styles make it a less cohesive listen than the other discs, it does give an excellent idea of the various lineups' extraordinary performing range.