radiosity:what is it for

Just the other day I watched a tutorial on radiosity. Unfortunately, the tutorial left more questions than answers. Does anyone have some sort of in depth guide that could help me understand the options?

Thanks.

have you tried the user manual? There’s a radiosity topic under Lighting. If you are trying for a conceptual understading, there’s wikipedia, and a Tutorial in the wiki that uses a skydome to give GI.