Environment Mapping is another invention of Blinn's. Environment Maps generally represent illumination from the enironment onto the object. The result looks good, but just as with Bump Mapping there are some artifacts. First of all, inter-reflections (reflections of object on itself) are not captured. Secondly, illumination is looked up via normals. This is only strictly correct when the source is infinitely far away, if the source of illumination is too close, the reflection will not line up. Regardless, the results are convincing and it is computationally cheaper than more sophisticated solutions like ray-tracing (in fact environment maps are sometimes used to incorporate ray-traced images into real-time environments).
I feel obliged to note that I'm using textures from Microsft's DirectX 9 SDK. I actually intern'd at Microsoft (it is a cool place ot work) and I think this is the lobby of building 19 or whatever building Bill Gates goes to work in. Although, I'm not entirely certain.