Infrastructure as Code (IaC) is a transformative approach that allows engineers to automate cloud infrastructure management by writing code rather than performing manual tasks, thereby reducing error and increasing scalability. This method is increasingly essential as modern applications, whether simple or complex, rely on diverse cloud infrastructures, necessitating consistent management and adaptation to evolving needs. The text introduces the concept and benefits of IaC, emphasizing its capacity to encode infrastructure configurations and changes in code, which can be reviewed, versioned, and replicated across different environments. It highlights the role of declarative code in IaC, which allows for the expression of desired infrastructure states and the automatic orchestration of necessary changes by IaC tools. Pulumi is presented as a noteworthy tool in this space, supporting various programming languages and cloud services, and offering a sophisticated "Automation API" for integrating IaC workflows into larger software projects. The series promises to explore the practical setup of IaC using Pulumi in its subsequent parts.