A memoir is any kind of nonfiction narrative writing that is based on the author's own recollections of events. Accordingly, the claims stated in the book are taken as factual statements. While memoir has traditionally been classified as a subgenre of biography or autobiography since the late twentieth century, the genre has evolved in terms of form, resulting in a more focused presentation of the author's life. Biographical works, such as biographies and memoirs, recount the events and times of one's life, while autobiography and memoir recount the events and times of one's own life, such as watershed moments and turning points in one's own life. The author of a memoir is referred to as a memoirist or a memorialist, depending on the context.