Best blues artists 1950 and on?

i'm making a blues album for my father and he says that he likes blues artists from around the 50's and up. i know he likes albert collins and bb king. can anyone tell me some really good early blues artists names? thanks.

T-Bone Walker is a MUST.
John Lee Hooker
Muddy Waters
Willie Dixon
Howlin' Wolf
Elmore James
Little Walter
Professor Longhair
Fats Domino
Smiley Lewis
Bo Diddley
Bobby Blue Bland
Slim Harpo
Buddy Guy
Junior Parker
Freddie King

Hm...Robert Cray. Muddy Waters.
Keb' Mo'. Also, From the Cradle by Eric Clapton is a blues album, and he has some other blues recordings.

Big Bill Broonzy is a must.

In terms of his musical skill, the sheer size of his repertoire, the length and variety of his career and his influence on contemporaries and musicians who would follow, Big Bill Broonzy is among a select few of the most important figures in recorded blues history. Among his hundreds of titles are standards like "All by Myself" and "Key to the Highway." In this country he was instrumental in the growth of the Chicago Blues sound, and his travels abroad rank him as one of the leading blues ambassadors.

Howling Wolf, Muddy Waters, Buddy Guy, Little Walter, Big Mamma Thorton, too many to list.

muddy waters
try also nat king cole

Don't leave out Stevie Ray Vaughn !!!!