The business value of components is derived from their configurability: like Lego or logic chips, they can be rewired and substituted to make new software end-products, keeping pace with business change.Like these hardware analogies, software component kits are viable only if there is a clear definition of the interface definitions that they all conform to. In the case of enterprise-scale components, this means much more than the COM, CORBA or RMI interface, and includes a common understanding of the business concepts and business rules.In this session, we'll look at what an architecture team needs to work out in order to make a kit of components coherent; how to use UML for that purpose; and some innovative modelling techniques well suited to CBD. The material is based on the presenter's Catalysis approach, developed with Desmond D'Souza (Objects, Frameworks and Components in UML, Addison-Wesley 1999).