There are far too many blues innovators to mention them all but listen to Delta pioneers Charley Patton, Son House and Robert Johnson to appreciate the roots of the genre. What are the best online ...
The first slide guitar recording (and first instrumental blues recording) was made by Sylvester Weaver for Okeh Records (No. 8109) in 1923, the A-side being "Guitar Blues" and the B- side "Guitar Rag.