This chapter introduces the book's research question and explains its relevance. The book is concerned with the concept of feasibility and how scientific assessments in the climate context engage with it. Feasibility is a central concept in political philosophy and has been prominently featured in recent climate discourse. Integrated Assessment Models are scientific models that project various climate futures for given climate goals and thereby provide scenario evidence on the feasibility of climate goals and different mitigation strategies. The central philosophical problem of the book is introduced as the value problem in assessing feasibility. The question is how we can assess the seemingly empirical concept of feasibility with value-laden models, which inherently and deeply depend on a range of value assumptions. The book attempts to explain how the models can contribute to assessing feasibility, while at the same time critically discussing their normative basis and evaluating modeling practices in light of a principal solution to the value problem. This chapter outlines the content and argument the book makes and what it contributes to the existing literature.