This chapter analyzes alpha fairness, perhaps the best known and most widely used fairness criterion that combines equity and efficiency. An important special case is proportional fairness, also known as the Nash bargaining solution, which corresponds to \(\alpha =1\) . The chapter states the easily derived alpha fairness solution subject to a budget constraint and carries out a marginal analysis of incentives to improve stakeholder efficiency. It cites past axiomatic and bargaining arguments for alpha fairness and discusses the issue of how to interpret the alpha parameter. In particular, it points out that stakeholders are incentivized to compete with each other when \(\alpha <1\) and incentivized to cooperate when \(\alpha >1\) .