GRIA is Grid middleware that enables use of the Grid in a secure, interoperable and flexible manner. It makes use of business models, processes, and semantics to allow resource owners and users to discover each other and negotiate terms for access to high-value resources. It implements an overall business process to find, procure and utilise resources capable of carrying out high-value, expert-assisted computations. By focusing on business processes and the associated semantics, it enables users to provision for their computational needs more cost effectively, and develop new business models for some of their services. Services from different providers can be combined together to create applications using a simple and easy-to-use API.