A case could be made that the rhythm section of drummer Sly Dunbar and bassist Robbie Shakespeare has had a larger impact on the sound and direction of Jamaica's music than even the charismatic Bob Marley. The so-called Rhythm Twins have had a hand in constructing over 200,000 sides and counting since they began playing together in 1975, an astounding number that is made even more amazing by the sheer high quality and steadiness of the duo's playing. The beginnings of that incredible run are chronicled here on this interesting little set, which covers 1969 to 1975. Sly and Robbie don't appear together until the 18th track here, John Holt's "Up Park Camp" from 1975, and most of the 21 tracks feature only one of the dynamic duo in residence, but the roots of what they would accomplish together are obviously already in place. Dunbar's drumming is a big part of why songs like the Upsetters' "Night Doctor," Dave & Ansel Collins' "Double Barrel," and Justin Hinds' "Say Me Say" have a deep and funky feel, while Shakespeare's steady, unobtrusive, but always clearly audible basslines hold songs like Slim Smith's "Blinded by Love" firmly in place. It all seemed preordained by the time Sly and Robbie were officially paired together in the Revolutionaries in the mid-'70s, locking in place like few rhythm sections before or since. The rest, as they say, is history.