With due respect to El34, Miles Davis's album "Kind of Blue" has no blues on it. It may FEEL bluesy, but blues is actually a vocal form characterized by an "aab" rhyming scheme. The primary form used on this album, which made it unique at the time it was recorded, was the use of the modal form (groupings of 3-5 note chords using several different scales, such as Dorian, Corinthian, etc.) Bill Evans, the featured pianist, was experimenting with modal forms for jazz improvisation. I am not familiar with any purely instrumental blues recordings, although recordings of early blues artists tend to be more instrumental than contemporary recordings. Big Bill Broonzy, Mississippi John Hurt, and Brownie McGhee are good examples of delta-style blues guitarists. If you want to check out some recent artists that feature a fair amount of instrumental work, you might like the album recorded by Drink Small for the Mapleshade Recordings label; Ronnie Earl and the Broadcasters album "Ballads and Blues"; and some of Stevie Ray Vaughn's work. One other idea: look into the recordings done for the Folkways label in the 1930's and 40's. They are available from the Smithsonian Institution, and are fabulous treasure trove of authentic blues and folk music.
