RACINE, Wis. (CBS 58) — It was a once-in-a-lifetime gathering of four music legends that would become one of the most famous moments in rock and roll history. But nearly 70 years later, questions remain about what really happened that day.

Author and historian Steven Rogstad joined Racine & Me to explore the fascinating story behind the "Million Dollar Quartet," an impromptu jam session featuring Elvis Presley, Johnny Cash, Carl Perkins and Jerry Lee Lewis.

It all began on Dec. 4, 1956, at Sun Records in Memphis, Tennessee.

Carl Perkins, who wrote and originally recorded the smash hit "Blue Suede Shoes," was in the studio for another recording session. A then-unknown piano player named Jerry Lee Lewis had been hired as a studio musician to accompany him.

What happened next was completely unexpected.

Elvis Presley, who had left Sun Records for RCA a year earlier, stopped by the studio with a female companion to visit his former labelmate. Johnny Cash, who had already become one of Sun Records' biggest stars, also made an appearance.

With all four musicians together, an impromptu jam session began.

The artists spent hours singing and playing music together. Fortunately, recording equipment was turned on during the gathering, preserving portions of the historic session.

However, the story doesn't end there.

Nearly two decades later, recordings from that day began to resurface. By then, Cash, Lewis and Perkins had become major stars, and interviewers wanted to know what they remembered about the legendary gathering.

But there was one problem: Their stories didn't match.

Each musician recalled the events of Dec. 4, 1956, differently. In fact, their accounts were so inconsistent that they sometimes appeared to be describing entirely different occasions.

The session eventually became known as the "Million Dollar Quartet," inspiring a Broadway musical of the same name that has continued to entertain audiences across the country.

Now, Rogstad is taking a closer look at the history behind the music.

In what he describes as the first historical study dedicated to the event, Rogstad examines the recordings, recollections and conflicting accounts to uncover what actually happened inside Sun Records that day — and perhaps more importantly, what didn't happen.

His research offers a fresh perspective on a legendary meeting that continues to fascinate music fans generations later.

To learn more about the Million Dollar Quartet and the mysteries surrounding that historic day, watch Steven Rogstad's interview on Racine & Me.

Catch Racine & Me Sunday mornings at 7 a.m. on WMLW The M.