Integration in general describes a union of parts making a whole. /But besides this meaning as a property of a system, “integration” additionally stands for the actions to be taken in order to achieve this property and thus has a behavioral perspective. describes a union of parts making a whole, which – as opposed to its parts – displays a new quality. A union of parts making a whole, which – as opposed to its parts – displays a new quality. We speak of integrated health information system if we want to express that it is a union that represents more than just a set of independent components. To achieve this integration, the components need to be interoperable. We expect positive consequences for the quality of information processing by integration. Different types of integration on the logical tool layer are data integration, semantic integration, access integration, presentation integration, contextual integration, and process integration. On the physical tool layer, physical integration is important.