Robert Lesley Conly aka Robert C. O'Brien was an American author best known for his 1975 novel 'Z for Zachariah', a post-apocalyptic story set in the wake of World War III. It follows sixteen-year-old central protagonist Ann Burden, who has survived a nuclear war having found a remote section of valley that is protected from nuclear fallout. The book was published posthumously and won an Edgar Award.O'Brien is also known for his 1971 novel 'Mrs Frisby and the Rats of NIMH'. His works have been filmed including The Secret of NIMH (1982), Play for Today (1970) segment 'Z for Zachariah' (1984), and The Secret of NIMH 2: Timmy to the Rescue (1998).Z for Zachariah (2011) is in production.