This course addressed the core requirements of users with disabilites and the aging population when using digital system via the standard HCI. Accessibility provides and contributed a lot of key features which are today part of usability. And due to its importance (individual, social, economic) it is legally required e.g. the European Accessibility Act (EAA), the Austrian "Barrierefreiheitsgesetz - BaFG" and the "Web Zugänglichkeitsgesetz". We learn about the core issues of Accessibility following the related standards as the Web Content Accessibility Guidelines (WCAG) and the EU301549.