The Grateful Dead is so old! They started in 1965 in California.
I didn't realize that started that long ago. I've never been a big fan of their music, to be honest. 
Lenny Kaye said that their music touches ground that most other bands don't even know exists.
Well, that is quite an endorsement. Jerry Garcia was one of the original members, right? I remember when he died. 
Yes, and they were the pioneers of the jam band world thanks to their diverse sound.
Oh, what's the jam band world?
Jam band
A jam band is a musical group whose live albums and concerts relate to a fan culture that began in the 1960s with the Grateful Dead, and continued with The Allman Brothers Band, and Phish which had lengthy jams at concerts. The performances of these bands typically feature extended musical improvisation ("jams") over rhythmic grooves and chord patterns, and long sets of music that can often cross genre boundaries. The Grateful Dead continued to grow their fanbase in the second half of the 1980s. In the mid-1980s
Grateful Dead
The Grateful Dead was an American rock band formed in 1965 in Palo Alto, California. The band is known for its eclectic style, which fused elements of rock, folk, country, jazz, bluegrass, blues, gospel, and psychedelic rock; for live performances of lengthy instrumental jams; and for its devoted fan base, known as "Deadheads". "Their music", writes Lenny Kaye, "touches on ground that most other groups don't even know exists". These various influences were