The HR profession is at a critical inflection point. It can evolve into a true decision science of talent, and aspire to the level of influence of disciplines such as Finance and Marketing, or it can continue the traditional focus on support services and program delivery to organizational clients. In this paper, we suggest that the transition to a decision science is essential and not only feasible, but historically predictable. However, we show that making the transition is not a function of achieving best-practice professional practices. Rather, it requires developing a logical, deep and coherent framework linking organizational talent to strategic success. We show how the evolution of the decision sciences of Finance and Marketing, out of the professional practices of Accounting and Sales, provide the principles to guide the evolution from the current professional practice of HR, to the emerging decision science of "talentship."