Following the release of their most acclaimed album of their decade-long career, "Deep Politics", Grails revisited "Black Tar Prophecies", their ever-expanding, enigmatic tapestry of eclectic experiments released in scarce limited editions that often disappear before most fans discover their existence.    'Black Tar Prophecies Vol's 4, 5 & 6" collects the last three volumes in the Black Tar series, originally released as a limited-edition 12", and a split LP with Finish psych-rockphenoms, Pharaoh Overlord.