B.B. King 1925-2015.
To the best of my recollection, I only saw him live once, at the Fillmore. His brand of blues was always a little too urbane for my taste, but obviously the guy was a one of a kind master.
I should add that when I was growing up it was an article of faith in musician and critics circles that the live album presented in its entirety below -- taped when B.B. was still playing what used to be called the chiltlin circuit -- was one of the greatest records ever made. And yes, it holds up.