Even accomplished film trivia geeks might need a minute to identify the man who penned such eternal expressions of tough-guy bluster as “I love the smell of napalm in the morning!” and “Go ahead, make my day.”

That’s because screenwriter and director John Milius, the self-described “Zen anarchist” whose industry power peaked and plummeted in the mid-1980s, remains by far the least known of the New Hollywood “movie brats” to have emerged from film school in the ’60s with a burning desire to put a boyish spin on classic genres.

Alas, the new documentary “Milius” isn’t likely to place the maker of “Big Wednesday” (1978) and “Red Dawn” (1984) on equal footing with his former buddies George Lucas, Steven Spielberg and Francis Ford Coppola, but it sure is reverential — and rewarding, too.

The film is available exclusively via Epix, an upstart streaming-video channel found on the Web and on devices including Xbox, iPad and Roku. (Free 14-day trials are being offered.)

A big, burly, sombrero-clad surfer and gun freak with the gift of gab and a propensity for button-pushing, Milius appeared “a man out of time” to Lucas and something of a menace to studio executives, not least the ones at MGM who saw him bring a pistol to a script meeting.

Whatever the reason, he wasn’t given official credit for co-writing 1971’s “Dirty Harry,” but in the documentary, Clint Eastwood confirms that the “make my day” line indeed belongs to Milius, whose manly poetry ran counter to the counterculture, eventually earning him high praise from Ronald Reagan and the scorn of the New Yorker’s Pauline Kael. (It’s no surprise to learn of Milius’ admiration for Theodore Roosevelt, whose claim that “it’s not the critic who counts” serves as the doc’s on-screen prologue.)

Directed with aptly adolescent enthusiasm by Zak Knutson and Joey Figueroa, “Milius” has top-tier talking heads, awesome clips from Milius’ signature works (remember the first “Conan” movie?) and an equal appreciation of the beauty and absurdity of a line such as “Charlie don’t surf!” from “Apocalypse Now.”

Whether Milius’ diminished career in Hollywood owes to political correctness or his own obnoxious behavior, his inimitable machismo is missed.

More Milius on VOD

Featuring a fresh-faced Charlie Sheen and Patrick Swayze as suburban teen warriors, Milius’ wildly jingoistic and widely reviled “Red Dawn” may have blown his director’s chair to smithereens, but the movie lives on (“Wolverines!”) via Netflix and Redbox Instant, et al.

“Big Wednesday,” wherein Milius brought Kurosawa’s seven samurai overseas to Malibu and traded their swords for surfboards, is the filmmaker’s magnum opus. Long available only on VHS and laserdisc, it’s now on iTunes in HD, and it looks spectacular.

Starring Arnold Schwarzenegger, the stunningly barbaric “Conan the Barbarian” (1982) is available for free (with ads) on HitBliss, and on Hulu Plus with subscription.

For those wanting to witness Milius after the fall, there are the director’s big-screen swan songs, “Farewell to the King” (1989) and “Flight of the Intruder” (1991), both on Epix and Netflix.