Deep Purple is not a conformist group. There never was, nor ever will be, any fawning to trends. What you do get from them are cutting edge performances based on a sound philosophy: "the music comes first". That music comes from within the core spirit of the band, nowhere else. They won't be bagged. Why?
In the sixties and early seventies they were described (by others) as "Progressive" or "Underground", when they made a conscious decision to depart from the "Hush" era in order to record the seminal album "Deep Purple in Rock".
"Fireball", "Machine Head", "Made in Japan" and "Who Do We Think We Are" quickly followed, and they were then tagged (along with Zeppelin and Sabbath) as leaders of the "Hard Rock" explosion. At this point began the gradual disintegration of the famous MK 2 line-up, (Blackmore, Gillan, Glover, Lord, Paice) and some long overdue individual R & R.
The eighties re-union as "Perfect Strangers" shook the world (again) with a fresh look at the music but with a bold detachment that stated "this is Deep Purple".