Razib at Gene Expression has a very informative post referring to the edited volume Epistasis and the Evolutionary Process (Wolf et al. 2000). I'm posting a reference myself because I want to remember and return to the topic later.
It's full of Sewall Wright goodness.
References:
Wolf JB, Brodie ED III, Wade MJ. 2000. Epistasis and the evolutionary process. Oxford University Press, New York.
