Different stakeholders have different concerns
• Different concerns imply different viewpoints
• Viewpoint a way of looking at a system from the position of a certain stakeholder with a particular concern
• defines creation, depiction and analysis of a view
• language, used models, notation, methods, analysis techniques
• View: whatever you see in a system from a particular viewpoint
• collection of system models
• conforming to the viewpoint
• Model:
• leaves out details irrelevant to concerns
• preserves the properties of interest with respect to those concerns