Work in progress. I have been trying to understand a bit about altruism via Price Equation. It is not too easy since I do not have background in that type of biology or mathematics. But mathematics seems quite simple and the equation is abstract and does not really require much biology except when it comes to some applications. An overview is two book reviews of different books. The first is a review of book by D.S. Wilson by H.Allen Orr The biology of being good to others. Another a review of book on George Price George Price, The Price equation and cultural group selection by Karthik Panchanathan. The second paper has formulae without proofs but mentions the references where details are available. Many of the details are in Steven A. Frank's papers, in particular this paper. In the section 'Abstract properties: Recursion and Group selection', he says "Essentially all modern discussions of multilevel selection and group selection derive from Price (1972a), as developed by Hamilton (1975). Price and Hamilton noted that the Price equation can be expanded recursively to represent nested levels of analysis, for example, individuals living in groups." The particular paper of W.D. Hamilton is 'Innate social aptitudes of man: an approach from evolutionary genetics'. I have read about half of both these papers and they seem readable with some work.