Nat King Cole. Bob Hope. George M. Cohan. Is it possible that what they accomplished, their very essence as artists and their impact on American culture, has all but been forgotten?

Yes, it is.

Legendary performers such as Cole, Hope and Cohan are almost entirely unknown to those less than 30 years old. And soon the impact of what these icons accomplished—their sheer brilliance—will be gone.

I mentioned the name of Nat King Cole in one of my college classes recently. Only a handful of my 70 students knew his name. Almost no one in the class knew that Nat King Cole was one of the finest jazz singers of the 20th century, with one of the most recognizable voices of any era.

Nobody in the class knew that Cole was the first black entertainer to host his own television show, which occurred, amazingly, in the mid 1950s. (That was nearly a decade before Bill Cosby’s breakthrough starring role in 1965 as secret agent Alexander Scott in “I Spy.”)

I mentioned many of his most famous songs: Mona Lisa;  Get Your Kicks on Route 66;  Unforgettable;  Ramblin’ Rose;  Answer Me, My Love; and Straighten Up and Fly Right.

But not one song title seemed to ring a bell.  I explained to them that prior to his singing career, Nat King Cole had already established himself as one of the best jazz pianists of his time, with the Nat King Cole Trio.   But I knew I was speaking to deaf ears.

I decided to also ask them about Bob Hope. Suddenly, many hands in the classroom waved. Several students knew that Hope was a comedian. And a few even knew that Bob Hope had entertained American troops overseas. But as I tried to discover what they knew about his artistic career, all the blank faces returned.

I told them how in the 1920s, Bob Hope had established himself on Broadway as perhaps the best known actor and singer. And how he took a huge risk and went into radio—then a very new and virtually unknown concept—and became the top radio star of his day. I told them that he then switched to motion pictures, and soon became the highest paid movie actor in Hollywood. And finally, how Hope took another risk — trying the next new innovation, called television—where he became the best known and highest paid television personality.

I marveled at what Bob Hope had accomplished:  reaching the top in theater, radio, movies and television, along with his decades of unpaid service entertaining  American military personnel. But I could tell they were not all that impressed. After all, that was a long time ago. A long, long time.

I knew that there was no chance that any of my students had heard of George M. Cohan. After all, he had begun writing hit songs over 100 years ago. But I offered them his name, just to see.

And, of course, no one recognized him.

But would they remember any of his music? Give My Regards to Broadway;  Over There;  It’s A Grand Old Flag; andI’m a Yankee Doodle Dandy. Not even a flicker of recognition. Just a few rolling eyes, some forced smiles and an occasional chuckle.

But when I began to sing the opening lines of Yankee Doodle, starting with  “I’m a Yankee Doodle Dandy, A Yankee Doodle, do or die. A real live nephew of my Uncle Sam,  Born on the Fourth of July…”  there was a sudden murmur, smiles, gestures and recognition! They knew the tune! They knew the tune! Amazing.

“You mean he wrote that tune over 80 years ago?” one young woman asked. Yes, I said, and it was actually more than 100 years ago!

“Gee,” she said. “I had no idea!”

Seeing their recognition of one of Cohan’s songs, I decided to tell my students that there was an excellent movie musical version of his life called Yankee Doodle Dandy.  In fact, I added, James Cagney won the Academy Award for his performance as Cohan in that film.

I really should have anticipated the next question.

“Who was James Cagney?”