Bill Cosby is a man who has worked at his craft.

He honed a stand-up routine for years, and did lots of TV and film projects before landing the huge hit “The Cosby Show” in the 1980s, which set the standard for gentle family comedy from that point forward.

He even went back to school in the middle of his career to earn a doctorate in education from the University of Massachusetts.

Even so, Cosby does not take complete credit for his success. When asked to think of a turning point in his career, a moment that helped shape him as a performer, he immediately went back to 1963.

“I was having the worst headache I ever had, and it was about 1:30 a.m. in this place in Greenwich Village, The Gaslight, and the boss looked at me and said, ‘You’ve got 20 people who want to see a show,’ ” Cosby, 73, said in a recent phone interview. “So I went up there with this terrible headache. They didn’t come to see me, I was the house comedian, and every performer on that stage was a folk singer; my job was to do 20 minutes of jokes in between.

“So I was looking to do 10 minutes and sit down, but I stayed on for three hours. Don’t ask me where it came from. In 1963, I didn’t have three hours of material. So I ad-libbed for two and a half hours.”

The next night, Cosby tried to ad-lib for a long stretch again, but couldn’t. He’s been learning from that experience ever since, trying to figure out what made such an event possible.

Where the stuff came from.

Cosby almost certainly won’t ad-lib for three hours when he performs Friday at the Augusta Civic Center. But he says he never tires of what he does.

“I’m a storyteller, so finding things and writing them and re-working them gives me a good feeling, and knowing that if they’re performed properly, people will smile. That’s a great feeling,” said Cosby.

Part of the reason Cosby plays Maine fairly often is that it’s not a long trip from home — he lives in Shelburne, Mass. For the Augusta show, he’ll probably fly from home just before the show and fly home right after.

Although times have changed since he started doing observational comedy in the 1960s and broke new ground with his educational cartoon TV series “Fat Albert and The Cosby Kids” in the 1970s, Cosby says his job hasn’t changed.

He looks at the idea of family, of how it affects all of us today, at this moment. Then he comes up with observations.

“Start with the idea of marriage,” he said. “We have people getting married later or not at all, and people living together and having children together without a marriage license is accepted. So you have heterosexuals without a piece of a paper, who want to have a family but don’t want to get married. But the oddity of it today is, you have homosexuals who want to get married and can’t.”

When asked what comedians make him laugh, Cosby quickly listed Sinbad, Steven Wright and Jerry Seinfeld. “Jerry is very, very exacting, and committed,” he said.

I thought I might get a chuckle from Cosby by doing my impersonation of Mushmouth, the mumbling character on “Fat Albert.” But Cosby politely declined.

“Please — don’t,” he said.

So I didn’t.

When a comedy legend gives you performance advice, you take it.

Staff Writer Ray Routhier can be contacted at 791-6454 or at: