Rumoursachieved greatness through turmoil, its double-album follow-up, Tusk, is the sound of a band imploding. 　　Lindsey Buckinghambegan to assume control of Fleetwood Mac during theRumourssessions, but he dominates Tusk, turning the album into a paranoid roller coaster ride where sweet soft rock is offset by feverish cocaine fantasies. 　　Christine McVieandStevie Nicksdon't deviate from their established soft rock and folk-rock templates, and all their songs are first-rate, whether it'sMcVie's "Over and Over" orNicks' "Sara."Buckinghamgives these mainstream-oriented songs off-kilter arrangements so they can fit neatly with his nervy, insular yet catchy songs. Alternating bracing pop/rockers like "The Ledge" and "What Makes You Think You're the One" with melancholic,Beach Boys-style ballads like "Save Me a Place" and "That's All for Everyone,"Buckinghamsubverts pop/rock with weird arrangements and unpredictable melodies, which are nevertheless given accessible productions. Even the hit title track is a strange, menacing threat punctuated by a marching band. This is as strange as mainstream pop gets, even pushing on the borders of the avant-garde. Because of its ambitions, Tusk failed to replicate the success of its two predecessors (it still went double platinum, though), yet it earned a dedicated cult audience of fans of twisted, melodic pop.