To meet business and technology needs, a new class of technology, called middleware is emerging. Integration based on middleware makes financial sense. Customers are reluctant to throwaway their existing legacy investment. Most mission-critical operations still run on mainframe-based systems due to concerns about security, reliability and speed. For this reason, companies are looking for robust connectivity and seamless interoperability between their mainframe and Internet applications. As corporations and vendors respond to these demands, they are discovering that middleware provides the essential glue that enables large complex business software to run effectively and reliably.