NEW YORK (AP) — A new documentary on Robin Williams tells the late comedian’s story mostly using his voice.

“Robin Williams: Come Inside My Mind” uses a wealth of archival footage to put viewers inside his thought process.

Director Marina Zenovich notes that Williams had a routine in the 1970s that invited people into his mind.

The film charts Williams’ rise in comedy up until his death in August 2014. Williams, who was suffering from dementia caused by Lewy body disease, killed himself at age 63.

Zenovich says the film is meant to be a celebration of Williams and his incredible talent.

The documentary, which includes interviews with David Letterman and Billy Crystal, premiered Monday on HBO and is available on its streaming service, HBO Now.