The Art of Nonfiction: Joan Didion
https://www.theparisreview.org/interviews/5601/joan-didion-the-art-of-nonfiction-no-1-joan-didion
This is Didion's 2006 interview in the well-known Paris Review's Art of series. The interview gives valuable insight into Didion's writing process and larger ideas about the genre of nonfiction. Also available from the Paris Review is her 1978 interview, The Art of Fiction.
Joan Didion
This is the link to Didion's official website, which includes information about all of her books and essays, as well as her biography.