On Saturday, director George Hickenlooper was found dead in Denver, where he had arrived to promote the upcoming premiere of his new film Casino Jack. His cousin, Denver’s Mayor John Hickenlooper—the subject of George’s 2009 documentary Hick Town and a current Colorado gubernatorial candidate—issued a statement saying that George died of natural causes. It was later confirmed by his father that Hickenlooper suffered a heart attack in his sleep. He was 47.

Hickenlooper was a former Roger Corman intern who first came to prominence with the Emmy-winning Hearts Of Darkness: A Filmmaker’s Apocalypse, which delved into the behind-the-scenes drama of the making of Francis Ford Coppola’s Apocalypse Now.

His career spanned both documentary and narrative features, including Factory Girl, Mayor Of The Sunset Strip, and The Man From Elysian Fields. He also directed Billy Bob Thornton in Some Folks Call It A Sling Blade, the short film that Thornton would later adapt into his name-making debut.

In addition to his films, Hickenlooper also wrote the book Reel Conversations: Candid Interviews With Film’s Foremost Directors And Critics, in which he spoke with subjects ranging from Louis Malle to Michael Cimino to David Lynch to Roger Ebert; like Hearts Of Darkness—and his other early films, Art, Acting, And The Suicide Chair: Dennis Hopper and Picture This: The Times Of Peter Bogdanovich In Archer City, Texas (about the making of The Last Picture Show sequel Texasville)—it revealed Hickenlooper as a serious student of filmmaking as an art form, one with an unusual amount of respect for the auteur theory and those who had established it.

Casino Jack, Hickenlooper’s latest and now final film, stars Kevin Spacey as disgraced lobbyist Jack Abramoff. Hickenlooper had been on a promotional tour that included presenting it at the Austin Film Festival last Thursday, just two days before his death. The film is due out in December.

Here's a Hickenlooper-narrated three-part documentary on the "Evolution Of Some Folks Call It A Sling Blade" that doubles as a fairly comprehensive look at Hickenlooper's early career.