Grateful Dead was an American rock band formed in 1965  in California
I've never heard their music before.
Well they are good. Lenny Kay attest to this by saying that  they touches on ground that most other groups don't even know exists"
I'll have to look them up then. How famous are they?
They were  ranked 57th by "Rolling Stone" magazine 
Wow that is quite the honor! Must be a great band.
So far they sold more than 35 million albums worldwide.
35 million? They must be really big then.