TERRY GROSS, HOST:

This is FRESH AIR. Tonight, HBO presents a biographical documentary called "Robin Williams: Come Inside My Mind." Our TV critic David Bianculli says it's very funny but gets even better when it turns serious.

DAVID BIANCULLI, BYLINE: This is the second time this year HBO has presented a thoughtful, well-researched, intimate documentary biography about a comedian who built a singularly successful comedy career, then died suddenly. The first was Judd Apatow's fabulous inspirational appreciation of Garry Shandling. The new one premiering today is called "Robin Williams: Come Inside My Mind." It's directed by Marina Zenovich, who is beginning to specialize in biographies of artists who have done great work but have complicated private lives. Her subjects have included Richard Pryor and Roman Polanski and now Robin Williams, whose onstage approach as a stand-up comic, whether he was changing subjects at warp speed or exploring one idea until it was a perfectly polished gem, was a wonder to behold.

(SOUNDBITE OF DOCUMENTARY, "ROBIN WILLIAMS: COME INSIDE MY MIND")

ROBIN WILLIAMS: This is Elmer Fudd sings Bruce Springsteen. (Impersonating Elmer Fudd, singing) I'm driving in my car...

(CHEERING)

WILLIAMS: (Impersonating Elmer Fudd, singing) I turn on the radio. I pull you a wittle (ph) closer. You say no.

BIANCULLI: After being diagnosed with what ultimately was identified as an Alzheimer's-like ailment called Lewy body dementia, Williams committed suicide in 2014 at age 63. But "Come Inside My Mind" is more about his life than his death. It explains, sometimes using audiotape of Williams being interviewed, including on FRESH AIR, how and why Robin Williams pursued acting and laughter as a young man, how he got into Juilliard, where he learned from the esteemed John Houseman, how he got his big break playing an alien named Mork on a guest appearance on ABC's "Happy Days" and how his sudden fame on "Mork & Mindy" in the 1970s led to years of excessive drug and alcohol use, how he crossed over from TV actor to movie star scoring with such films as "Good Morning, Vietnam," "The Fisher King" and "Mrs. Doubtfire" and how he teamed with Billy Crystal and Whoopi Goldberg for annual Comic Relief benefits for the homeless.

There are samples from all these phases of his career, and there are outtakes, too - plenty of them, including some very raw comedy. But what's even more interesting are the comments from other very funny comics who drop their guard here and speak very seriously about both the comedy and personality of Robin Williams, like David Letterman, who started as a stand-up about the same time in the same comedy clubs and watched Williams with awe...

(SOUNDBITE OF DOCUMENTARY, "ROBIN WILLIAMS: COME INSIDE MY MIND")

DAVID LETTERMAN: In my head, my first sight of him was that he could fly because of the energy. It was like observing an experiment.

BIANCULLI: ...And Steve Martin, who starred with Williams in a stage production of "Waiting For Godot"...

(SOUNDBITE OF DOCUMENTARY, "ROBIN WILLIAMS: COME INSIDE MY MIND")

STEVE MARTIN: His character was interestingly hurt. And he played it very vulnerable, as I think he was in life, too. On stage, he was the master and charge and funny and quick. And in life, you know, he wasn't onstage anymore. I just felt a little bit of a - I think he was really comfortable onstage and less comfortable off stage. I always felt him holding himself together.

BIANCULLI: ...And Billy Crystal, who shares and talks about some of the private phone messages his old friend would leave on his answering machine.

(SOUNDBITE OF DOCUMENTARY, "ROBIN WILLIAMS: COME INSIDE MY MIND")

BILLY CRYSTAL: Wherever I was, when the phone would ring and I'd look at it and I'd see the 415 area code, I knew it was him. I knew it was going to be something really good.

(SOUNDBITE OF VOICEMAIL TONE)

WILLIAMS: Hello, Mr. Crystal. My name is Sam (ph). I'm calling on behalf of the Syphilis Society. It's a group of us who work to help people with their syphilis. I don't have syphilis myself, but I represent those who do. Thank you. We'll try calling back. (Unintelligible) Thank you.

BIANCULLI: We also hear from some of the people from Robin Williams' private life - his brother, his first wife, his son Zak and even from the son of Garry Marshall, the TV producer who made Williams a star with "Mork & Mindy." The crazy energy described by Letterman, according to Scott Marshall, led to a change in the way live TV sitcoms were filmed.

(SOUNDBITE OF DOCUMENTARY, "ROBIN WILLIAMS: COME INSIDE MY MIND")

SCOTT MARSHALL: He would run around the stage, you know? He would run around and do crazy things all the time. And there was, like, union cameramen. He would do something great. My dad would go, did you get that? Did you get that? The cameraman would say, he didn't come by here. You got to capture this. He's a genius. And the cameraman said, if he's such a genius, he can hit his mark. And so my dad said, wow, this is - got to figure this out. The sitcom up until then was always three cameras. So he brought in a fourth camera, kind of a hand-held camera just to follow Robin. And that became the standard. Now every sitcom has four cameras now because of that.

BIANCULLI: When ABC was about to launch "Mork & Mindy" in 1978, it introduced the show's star at TV critics during the ABC portion of the press tour not with a press conference but with this unknown comic performing a mostly ad-libbed standup act. Every critic there - and I was one of them - left that night convinced that whatever might happen to "Mork & Mindy," this Robin Williams guy was a comedy force to be reckoned with. You'll laugh a lot as you watch "Robin Williams: Come Inside My Mind." But at the end, you'll feel a sense of loss, too, which I suspect are precisely the goals this biography had in mind.

GROSS: David Bianculli is editor of the website TV Worth Watching and author of "The Platinum Age Of Television: From 'I Love Lucy' To 'The Walking Dead,' How TV Became Terrific." He reviewed "Robin Williams: Come Inside My Mind," premiering tonight on HBO.

Tomorrow on FRESH AIR, we'll talk about how Wisconsin went from blue to red. Our guest will be Dan Kaufman, author of "The Fall of Wisconsin," about how a state long known for progressive politics came to embrace a governor who attacked public employee unions and helped send Donald Trump to the White House. It's a story of dark money, gerrymandering and Democratic complacency. I hope you'll join us.

(SOUNDBITE OF THE FRESH CUT ORCHESTRA'S "THE MOTHERS' SUITE, MOVEMENT III - RITUAL OF TAKE")

GROSS: FRESH AIR's executive producer is Danny Miller. Our engineer today is Adam Staniszewski. Our associate producer of digital media is Molly Seavy-Nesper. Roberta Shorrock directs the show. I'm Terry Gross.

(SOUNDBITE OF THE FRESH CUT ORCHESTRA'S "THE MOTHERS' SUITE, MOVEMENT III - RITUAL OF TAKE") Transcript provided by NPR, Copyright NPR.