B2B organizations have begun to realize that, to meet post-sale customer relationship needs, they must establish a customer success function that complements the efforts of sales, technical support, and customer service. Customer success supports every stage of the customer lifecycle, through actions that are distinct from, but aligned with, sales and service. In this report, we describe the customer success function, why it’s needed, and present a framework for mapping customer success efforts to the stages of the customer lifecycle that creates long-term value by keeping customers happy and engaged.