The article introduces various manuscripts published in the January 2004 issue of the journal "IEEE Network," on middleware technologies for future communication networks that describe the latest results of cutting-edge middleware R&D efforts, that in turn focus on the next generation of mobile and fixed networks and services. Middleware is a systems software that resides between the applications and the underlying operating systems and networks, and provides reusable services that can be composed, configured, and deployed to create networked applications rapidly and robustly.