In the early '80s, the celebrated producer Jah Thomas recorded a handful of albums at King Tubby's studio using the even more celebrated Roots Radics band for backup. During this period, he worked with such stellar singers as Barrington Levy, Sugar Minott, and Johnny Osbourne, but the instrumental performances he elicited from the Roots Radics stand easily on their own. This compilation is something of a curiosity: It consists, for the most part, of typically top-notch Roots Radics rhythms dubbed up creatively, but tastefully, by Thomas. But it also includes some anomalies -- mediocre digital rhythms that involve no analog instruments and could have been produced by anyone with a basic understanding of middle-period dancehall clichés. "Dub on the Nile" is an especially egregious example, a dreary one-chord vamp that sounds like Sly & Robbie having a bad day. One wonders whether the Radics actually had anything to do with these tracks. ("Into the Lions Den Dub," however, is a much more interesting and effective example of the digital approach.) Luckily, these disappointing exercises are sufficiently outnumbered by great Radics performances to make the album recommendable.