Today is the 75th anniversary of Robert Johnson's first recording session with producer Don Law at the Gunter Hotel in Dallas, Texas. If ever there was a serious "moment" in popular music history, Johnson's sessions in Dallas would be among the biggest along with Elvis'  "That's All Right, Mama" for Sun and Ray Charles' session to record "I Got A Woman" for Atlantic.

Peter Guralnick is the author of acclaimed biographies of Elvis Presley (Last Train to Memphis and Careless Love) and Sam Cooke (Dream Boogie) and is currently writing the biography of Sun Records founder, producer and recording engineer Sam Phillips, due in 2013. Guralnick also wrote Sam Cooke—The Legend for VH-1, which won a GRAMMY in 2004 for Best Long Form Music Video. Guralnick is the author of numerous collections profiling blues, country, rockabilly, and rhythm and blues artists, including Searching for Robert Johnson. Legacy recently released a new box set of Johnson's recordings to celebrate the blues legend's 100th birthday. caught up with the author in Nashville.

How old were you when you first heard Robert Johnson?

I first heard Robert Johnson, I guess, when Sam Charters' The County Blues first came out on RBF Records. It had "Preachin' Blues" on it. I must have been around 16. I can remember vividly the day I discovered the album – no advance warning, no idea it was coming out – when I walked into Sam Goody's on 49th or 50th in NYC in the fall of '61. I was 17, a freshman at Columbia, and not only was King of the Delta Blues Singers in the blues bin but so was Big Joe Williams' Piney Woods Blues on Delmark (I think it still had the "k”). I bought them both and spent the rest of the day – the rest of the week! – listening to them over and over.

What makes Robert stand out from his contemporaries like Son House, Tommy Johnson or even the great Charlie Patton?

To me, the most extraordinary thing about Robert Johnson is his compositional approach. Music, lyrics, vocals are all of a piece – neither incidental nor coincidental. I think that's why his music continues to have such a cross-everything appeal.

In past biographies, Robert's traveling companions have stated Robert listened to a wide range of music from Jimmie Rodgers to Sons of the Pioneers.

That's what Johnny Shines said. "Tumblin' Tumbleweeds," right? Bing Crosby, too. Knowing Johnny (and Robert Jr. Lockwood, too), I can believe it! There was no such thing as confinement by category. Plus they were all making a living with their music. Polka, anyone?

Producer Don Law commented that Robert was shy in the studio and suspicious of musicians stealing his style. Was he aware he was breaking ground?

I think the shyness has been overemphasized – and I think he was aware of breaking new ground. Once he found his own style, he picked up followers everywhere he went. There was never any question of who was the leader, and when he died, long before the greater world had ever heard of him, long before he was ever discovered by a white audience, they carried his music on.