If a group of friends pools their money together to buy a pizza, how do they decide who pays how much? And when a team of engineers builds a product, how should the profits be split to reflect each person’s unique contribution? This chapter introduces two powerful, yet very different, answers to questions like these — the Shapley value and the nucleolus. Both are specific ways to split the total value in games where players can form groups, offering prescriptions for fair or stable allocations when cooperation creates value.