Andrey Andreyevich Markov was a Russian mathematician, especially well known for the concept of a Markov model or Markov process
Used on Chap. 14: page 323
Also known as Andrey Andreyevich Markov
Links:
mathshistory.st-andrews.ac.uk: St Andrews: Andrei Andreyevich Markov (1856-1922) - Biography
Wikipedia: Andrey Markov