Hey Erica,
Did you feel that?
Muddy Waters is in many ways an ideal artist to start with in exploring blues, because he was the linchpin of the earlier country/Mississippi Delta blues and the electrified Chicago sound he later pioneered. He was also a respected bandleader with many significant blues musicians (Otis Spann, Little Walter, Jimmy Rogers, Willie Dixon, Big Walter Horton, Junior Wells, Buddy Guy) passing through his band. Muddy was a complex, expressive vocalist as well - there is so much "feeling", depth and color in his singing. An area in which I think Muddy was a bit unheralded was as a slide guitarist. His slide playing had that same microtonal phrasing his voice had. He played a vital role in resurrecting the use of (amplified) slide guitar in the '60s.
The two above albums are the first blues records I ever purchased. I still believe they are good guides for anyone embarking on a discovery of blues.