"VERY SEMI-SERIOUS: A PARTIALLY THOROUGH PORTRAIT OF NEW YORKER CARTOONISTS," AN OFFBEAT MEDITATION ON HUMOR, ART AND THE GENIUS OF THE SINGLE-PANEL CARTOON, DEBUTS DEC. 7, EXCLUSIVELY ON HBO

Every Tuesday, eager cartoonists line up outside the office of New Yorker cartoon editor Bob Mankoff to show off their work. After he sifts through thousands of submissions, the magazine ends up buying and publishing about 15 each week. Whether they leave readers amused, inspired or even a little baffled, these iconic cartoons have been an instantly recognizable cultural touchstone over the past 90 years.

Directed by Leah Wolchok and produced by Davina Pardo, VERY SEMI-SERIOUS: A PARTIALLY THOROUGH PORTRAIT OF NEW YORKER CARTOONISTS, offers a window into The New Yorker, the undisputed standard bearer of the single-panel cartoon, and an unprecedented glimpse into the process behind their creation and publication. The lighthearted yet poignant feature-length documentary debuts MONDAY, DEC. 7 (9:00-10:30 p.m. ET/PT) exclusively on HBO.

Other HBO playdates: Dec. 7 (3:45 a.m.), 10 (10:45 a.m., 5:45 p.m.), 13 (9:10 a.m.), 15 (3:45 p.m.) and 19 (2:30 p.m.)

HBO2 playdates: Dec. 9 (8:00 p.m.), 15 (11:00 p.m.) and 22 (10:15 a.m.)

The documentary will also be available on HBO NOW and HBO GO.

Revealing The New Yorker's weekly open-call cartoon submission process, VERY SEMI-SERIOUS follows Bob Mankoff as he strives to nurture new talent and represent the magazine's old guard, while also considering how his industry must evolve to stay relevant. Mankoff has been cartoon editor of The New Yorker since 1997 and has also had more than 900 of his own cartoons published in the magazine since the 1970s.

The New Yorker's signature brand of subtle, contemplative humor, Mankoff muses, can "make the strange familiar, or the familiar strange." Editor David Remnick notes that cartoons have been a major component since The New Yorker began as a humor weekly in 1925. The film showcases vintage works from William Steig, Charles Addams, Peter Arno and James Thurber, whose "Touché!" cartoon Mankoff praises as "immediate, visual, and comic."

In the '60s, cartoonists like Mort Gerberg, Sam Gross and Lee Lorenz sold cartoons to a number of magazines, many of which have since shuttered. Though a few still make a living solely on cartoons, most of today's new generation also have "day jobs," including Carolita Johnson (a pattern model), Zachary Kanin (a writer for "Saturday Night Live") and Bruce Eric Kaplan (a writer-producer on HBO's "Girls").

In addition to behind-the-scenes footage with Mankoff, Remnick and other New Yorker staffers, VERY SEMI-SERIOUS profiles legendary cartoonists such as Roz Chast, Mort Gerberg and George Booth, as well as young hopefuls like Liana Finck and Ed Steed, as they discuss their cartoons and go through the process of submitting to - and often being rejected by - the magazine each week.

Among the cartoonists featured:

George Booth, now 89, sold his first cartoon to The New Yorker in 1969, and is one of the magazine's most beloved and prolific contributors.

Roz Chast says that when she started selling cartoons to The New Yorker in the late-'70s, one critic commented that the editor must have owed her father money. To date, more than 1,230 of her cartoons have been published.

Liana Finck is a young aspiring cartoonist with a soft-spoken demeanor and off-kilter sense of humor. Mankoff is drawn to Fink's unique sensibility and encourages her to keep submitting, but warns her that "reading a cartoon shouldn't be a struggle."

Emily Flake, a new mom, doesn't want to be pigeonholed into "women's issues," and has been submitting cartoons about "the darker side of motherhood."

Mort Gerberg, who has had over 200 cartoons published in The New Yorker, shows a print of the first cartoon he sold, depicting two women in a cathedral, with the caption "I've always been partial to high ceilings."

Ed Steed is a young artist who "came out of nowhere," according to Remnick. Raised on a farm in the UK, and even more soft-spoken than Finck, Steed has already sold close to 50 cartoons to the magazine, even though he encountered The New Yorker for the first time just two years ago.

In early 2015, The New Yorker moved from midtown to its new offices at One World Trade Center. Mankoff, who recently published "How About Never - Is Never Good For You?," a memoir named after his most famous cartoon caption, continues to meet with cartoonists there every Tuesday. Flipping through his own archive, a black book of cartoons dating back to 1977, Mankoff says, perhaps only half-jokingly, "This would make a good tombstone."

VERY SEMI-SERIOUS: A PARTIALLY THOROUGH PORTRAIT OF NEW YORKER CARTOONISTS is directed and produced by Leah Wolchok; produced by Davina Pardo; executive producers, Regina K. Scully, Deborah Shaffer and Bruce Sinofsky; director of photography, Kirsten Johnson; co-producer, Joanna Sokolowski; editors, Nels Bangerter and Scott Stevenson. For HBO: senior producer, Sara Bernstein; executive producer, Sheila Nevins.