Since copyright laws were virtually non-existent in Jamaica for most of the 20th century, it is common to hear innumerable mutations of any given riddim track. Discerning the creators of each song can be a daunting task. From 1967 to ’70, however, the Sound Dimension was the house band at Studio One, creating memorable cuts for the lyrical pantheon of Jamaica to sing and toast over. This 18-song collection of instrumentals shows how pivotal these men were in the sonic architecture of reggae. Songs like “Summertime,” “Rockfort Rock,” and “Reggae Time”–some unheard outside of the living rooms of vinyl junkies–form an excellent window on island life before drum machines became the craze.