Walter M. Miller Jr.
Regarding this, wHEN WAS A Canticle for Leibowitz first published?
October 1959
Subsequently, question is, how many pages is A Canticle for Leibowitz? 320
Also asked, where is New Rome in A Canticle for Leibowitz?
IIRC, New Rome is somewhere in old Missouri. Central and with easy communication, since it lies along the Mississippi (it was better detailed in Saint Leibowitz and the Wild Horse Woman, which I haven't read nearly as recently).
Who is Leibowitz?
Samuel Simon Leibowitz (August 14, 1893 – January 11, 1978) was a Romanian-born American criminal defense attorney, famously noted for winning the vast majority of his cases, who later became a justice of the New York State Supreme Court.