If Alan Alda hadn’t needed dental surgery about 30 years ago, he might not have written his new book.

The dentist, with scalpel in hand, warned Alda that there would be “tethering” as a result of the procedure. When Alda asked what he meant, the doctor replied “tethering,” as if he should know. Weeks later on a film set, Alda found out when a drooping upper lip made it impossible for him to smile.

“That was sort of a key moment when I think back on the worst moment of communication I ever had,” says Alda, 81.

Since then, the Emmy winner, who starred in “M*A*S*H” for 11 seasons, has been an advocate for improved communication, leading to the establishment in 2009 of the Alan Alda Center for Communicating Science at Stony Brook University. Alda’s experiences, including his improv training, and the techniques taught at the center form the basis of his bestseller “If I Understood You, Would I Have This Look on My Face?” (Random House, $28).

The former Water Mill resident will be on hand Thursday for “An Evening With Alan Alda,” a sold-out event at the Cinema Arts Centre in Huntington, which will include career clips, an interview and a book signing. Alda recently talked about the science of communicating, “M*A*S*H” and more.

You’ve been married for 60 years. Is good communication the secret?

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My wife [Arlene] says that the secret to a long marriage is a short memory. She would laugh heartily if I said we were married 60 years because I’m such a good communicator. But we wouldn’t be married that long if we didn’t listen to each other and understand what the other’s perspective is.

Has using the communication exercises you describe in the book made you a better actor?

Absolutely. Improv training was the only training I ever had as an actor, and when I call upon those techniques I’m at my best.

Is it true that you originally didn’t want to do “M*A*S*H”?

I was making a movie at the Utah State Prison when I got the “M*A*S*H” script. I thought it was terrific. I told my wife on the phone that I didn’t see how I could do it because it had to be made in California and we lived in the East. I said this thing could run as much as a year. [Laughs.] She said if it’s that good, maybe we could solve it with travel. It worked out.

What was your favorite moment doing “M*A*S*H”?

Between shots, we almost always sat around in a circle of chairs. It meant quite a lot to the success of the show because the camaraderie we had in real life spilled over in front of the camera. All we did was keep each other laughing.

You also hosted “Scientific American Frontiers” on PBS. Were you always interested in science?

Yes, even as a little boy. I had a card table where I was doing what I thought were experiments. I would try mixing things I found around the house to see if I could get them to blow up. If you mix toothpaste with face powder, I established at an early age, it won’t blow up. There actually were things that I couldn’t reach that would blow up. It’s a good thing I couldn’t reach them.

Do you have any new acting projects?

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The last thing I did was “Horace and Pete,” a web series [about a family-run bar] with Louis C.K. It’s on Hulu now. . . . And I have started Alda Communication Training, which offers communications training to corporations, and the profits go to the center at Stony Brook. It’s a little like the Paul Newman model, but instead of selling spaghetti sauce, we sell empathy.