John Maynard Smith, (1982). Evolution and the theory of games. Cambridge University Press.
The concept of evolutionary stable strategy was first introduced by Professor John Maynard Smith which was then largely adapted in ethology and biology about the evolution of behaviour. This books address the whole theory and explores the genetic systems, game theory and animal behaviour.
The evolution of behaviour discussed in this book is directly applicable to Risk. A player who plays repeatedly is subject to an evolutionary game play by his opponents. The dynamics behind this are quite fascinating. Knowing the mathematics behind the complexity may actually help to improve your Risk game. Instead of focusing on winning the current game, you can start to focus on winning all games. Your moves will be different if you want to win over and over again than if you just wanted to win the next game.