Robert C. O'Brien through his novel "Z for Zachariah" gave a kind of new dimension to the science fiction writing. Robert C. O'Brien was the pen name that Robert Leslie Conly used in his books as a writer. The present novel "Z for Zachariah" was published posthumously in 1974. It is a post-apocalyptic science-fiction novel.The author passed away in 1973. When he died, the book was incomplete, but his wife Sally M. Conly and their daughter Jane Leslie Conly began to work on the novel with the help of the notes that the author had left, and eventually completed the novel in the following year after the author's death.