With its longer song lengths and reworkings of B-sides and previous singles, songs given to other acts and a cover of an early house classic, Introspective could almost be seen as an addendum to the Pet Shop Boys discography. But Introspective fully thrives on being a truly dance-centered version of the Tennant and Lowe dynamic, and the remarkable range from their Miami freestyle nod “Domino Dancing” to a radical house remix of their cover of “Always On My Mind,” not to mention the astoundingly arch and driving opener “Left To My Own Devices,” says it all.

Now THIS is an act that knows they’re in their Imperial Phase. The absolute swagger of taking on Elvis and winning (“Always on my Mind”), of writing one of the greatest pop songs of the era for someone else then taking it back and making it your own (“I’m Not Scared”, formerly for Patsy Kensit / Eighth Wonder), of singing about “Che Guevara and Debussy to a disco beat” (“Left to my Own Devices”), of singing “I want to hear somebody bark” over a cutting edge dance beat and making it desperately affecting (“I Want a Dog”), and still having number one hits is breathtaking when you think about it. This collection of single remixes, b-sides and new tracks was the sound of house music taking over the UK, of the nineties dawning early — and of the Pet Shop Boys on top of the world.