This Book examines the topic of non-financial reporting, focusing on the two main types of reporting: Sustainability Reporting (SR) and Integrated Reporting (IR). It includes an overview of the research, with the aim of highlighting the diversity of approaches used by researchers as well as the multiplicity of facets that concern non-financial reporting. The chapters address the main macro-themes related to non-financial disclosure and attributable to the following categories: 1. The factors that influence the quality of non-financial reports; 2. The different types of non-financial disclosure (such as, for example, Circular Economy disclosure or Intellectual Capital Disclosure); 3. The motivations behind the adoption of non-financial communication, explained, for example, according to the legitimacy theory as the need for companies to improve or restore their reputation on the market. For each category, the volume provides examples of studies and starts the discussion for further necessary insights.