This chapter focuses on the customer and the services which banks offer to customers. It begins by filling in some of the details about the customers of banks and modern banking services. In this context it gives attention to how the relationship between banks and their customers may be characterized as a matter of law. Contract emerges from this as the overarching feature of the relationship; thus, the second and third sections of the chapter discuss banking contracts and their regulation. The final section turns to a specific banking service, the taking of deposits. Historically this has been the core banking service, and deposit-taking has been central to any definition of banking.