The International Integrated Reporting Council (IIRC) Framework is arguably the most important guide for companies willing to implement Integrated Reporting (IR). This chapter offers a review and discussion of the most important guiding principles and content elements that are the backbone of the IIRC Framework. It also compares the Framework with the main sustainability reporting standard, the Global Reporting Initiative (GRI) Guidelines. Following such a comparison, we argue that IR can be seen as an evolution of financial reporting rather than as sustainability reporting. Finally, the chapter discusses some of the most critical aspects of the IIRC Framework, such as its approach towards materiality and capitals. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.