Information design is a multi-disciplinary, a multi-dimensional, and a worldwide consideration. It is not possible to develop firm design rules telling the information designer exactly how to best design a message and develop information sets. Based on research it is possible to formulate several ID-principles and then develop a number of guidelines for the design of effective and efficient information sets. Several principles are labelled as “functional principles.” Guidelines based on these principles assist the information designer to design information sets that are well suited for the intended receivers. However, the information designer will always have to consider one of the main ID-principles: “it depends.”