"Knocking at Your Back Door: The Best of Deep Purple in the 80's" is a compilation album by the British hard rock band Deep Purple. It is a compilation of tracks from three albums, Perfect Strangers (1984), The House of Blue Light (1987), and the live album Nobody's Perfect (1988). This best-of of eighties Deep Purple marks the return of the Mark II line-up, and what a return! Although purists will disagree with compilations such as this, it has to be said that weeding out the dross makes this a stunning disc. From the sheer exuberance of the title track, to the monumental re-working of 'Hush,' there is very little to dislike here.