This chapter introduces readers with a background in physics to key ideas in economics and finance, presenting them in a language and conceptual framework that will feel more familiar. Although such topics may seem recognizable, whether due to their impact on professional life or their widespread presence in everyday media—they often lack rigorous interpretation from a physical science perspective. Our goal is to clarify why these domains are not merely external interests but natural extensions of physical reasoning applied to different classes of systems. In doing so, we argue that finance and economics are not “applications” of physics in the traditional sense, but instead represent new territories where physical principles and modeling approaches find renewed relevance.