We present the rationale, architecture, and implementation of an intelligent room, built upon a dense radio-based network of diverse electronic sensors, and interfaced with a cluster of dedicated computers. This room (an "iRoom") is capable of high-order tasks in event detection, analysis, processing, deduction, and inference. Initial focus has been to provide answers to the "Five W's" regarding a human visitor: Who, What, When, Where, and Why. The foundation technique that underpins this research is Sensor Fusion: the mathematical combination of disparate sensor reports and analyses into a rational result which is more accurate and more useful than its constituent parts.