Of all the billions of us who have looked up at the moon with awe and wonderment through the centuries, only 12 have actually set foot on the lunar surface.

Five are now gone — including Neil Armstrong, the first to walk the moon. Still with us: Buzz Aldrin (age 86), Alan Bean (83), David Scott (83), John W. Young (85), Charles Duke (80), Harrison Schmitt (81) and Chicago native Eugene Cernan, who on Dec. 13, 1972, left his footprints on the lunar surface and climbed the ladder of the lunar module of Apollo 17.

He was the last man on the moon.

In Mark Craig’s beautiful and breathtaking and stirring documentary “The Last Man on the Moon,” the 81-year-old Cernan comes across as an articulate, thoughtful, even philosophical man of pure courage, warm humor, strong emotions and more than a touch of vulnerability. Through extensive interviews with Cernan and other key players in the Apollo program, archival footage, visually impressive re-enactments and treasured home video footage and still photos, “The Last Man on the Moon” is a memorable portrait of a genuine American Space Cowboy.

Paul Newman could have played Cernan in a biopic.

As sharp as ever and a born storyteller, Cernan recounts his multiple and dangerous missions, from the Gemini 9 spacewalk to the Apollo 10 flight (essentially a dress rehearsal for the moon landing, as Cernan, Young and Thomas Stafford did everything Apollo 11 would do, just short of an actual landing).

We also learn of Cernan’s early days as something of a daredevil pilot with the Navy. Over a nighttime backyard barbecue, Cernan’s old Navy buddy, former Naval Aviator Fred “Baldy” Baldwin, ribs Cernan about having average bombing skills at best. Cernan takes a beat, points up to the moon and says, “That’s 240,000 miles away, and I hit that.”

At times Cernan’s recollections are bittersweet. Returning to the forgotten remnants of past launch sites, he says, “I almost wish I didn’t come here.”

As Alan Bean acknowledges, those dashing “Right Stuff” astronauts of the 1950s-1970s “were not very good husbands [and not] very good fathers, either.”

Cernan’s first marriage did not survive his tenure as an astronaut. “If you think going to the moon is hard, you ought to try staying at home,” says his ex-wife, Barbara Jean Atchley.

When Cernan returned home from the Apollo 10 mission, he told his daughter Tracy, then 9, all about his grand adventures in space. When he was finished, she said, “Now that you’ve gone to the moon, Daddy, can you take me camping?”

Some 40 years later, Cernan sits on a swinging bench on his ranch with his grown daughter, and talks about all those times he wasn’t around to take her camping.

“It was a very selfish life,” he says. “I was gone and gone and gone and gone and gone …”

Cernan famously drew his daughter’s initials in the lunar dust just before leaving the moon. It’s the best and coolest graffiti of all time.

He also spoke with poetic grace just before his walk on the moon would come to an end, saying in part: “As I take man’s last step from the surface, back home for some time to come … I’d like to say … America’s challenge of today has forged man’s destiny of tomorrow. And as we leave the Moon … we leave as we came and, God willing, as we shall return with peace and hope for all mankind.”

This is a great documentary about a great man.

★★★★

Gravitas Ventures presents a documentary directed by Mark Craig. Running time: 95 minutes. No MPAA rating. Opens Friday at the Gene Siskel Film Center.