Robin Williams, who has been four years absent from the world, is now the subject of a bitter-sweet new documentary. Directed by Marina Zenovich, this intimate portrait examines one of the world's most beloved and inventive comedians, and takes you closer to the manic engine of Williams' brilliance and pain.

"Robin Williams: Come Inside My Mind" honors the late actor/comedian with a story that is both poignant and joyful.

MARINA ZENOVICH DIRECTOR, "ROBIN WILLIAMS: COME INSIDE MY MIND" "I mean, we wanted this film to be kind of a celebration of Robin and what's so great is hearing people say the film is so inspiring."

Williams suffered from dementia caused by Lewy body disease and killed himself in August 2014, aged 63. Employing a wealth of archival footage, the documentary is told mostly through the iconic performer's own voice.

MARINA ZENOVICH DIRECTOR, "ROBIN WILLIAMS: COME INSIDE MY MIND" "Yeah, the film is told with Robin's voice and that was a conscious choice that we felt like we wanted you to be able to come inside his mind, which is actually the name of a routine he did in the '70s."

It also offers intimate interviews with some of his closest family and friends, including David Letterman, Billy Crystal and Williams' son, Zak.

MARINA ZENOVICH DIRECTOR, "ROBIN WILLIAMS: COME INSIDE MY MIND" "I get sad when I think about Billy and Robin because when I interviewed him you could really feel a sense of loss. And it was important that we showed just their relationship. And I love the line in the movie when he says, 'Everyone wanted something from him. I had no agenda. I just liked him'."

Zenovich said her entire team "hand crafted" the project with love.

MARINA ZENOVICH DIRECTOR, "ROBIN WILLIAMS: COME INSIDE MY MIND" "It was made with so much love and respect for Robin, between the composer and the editors and the researchers. And I think we all just wanted to celebrate him and share him. And if people can walk away with a greater understanding of who he was and what he tried to do and how generous he was and what a great mind he had, then I think we are happy."

CGTN.