There have been many Pretenders, but there is just one Chrissie Hynde: a walking combination of Fifties rockabilly, Sixties girl-group soul and Seventies punk who created some of the greatest rock and pop of the Eighties and beyond. The five-disc box set Pirate Radio documents the fluctuations of the Pretenders -- through good albums and bad, and through a series of lineup changes -- with Hynde serving as the immovable object.