What is known about consciousness?

Three questions I would like to find some answers for are:

What is known (to a high degree of certitude) about consciousness?
What experimental tests have been able to verify predictions made?
What predictions have been made that nobody has managed to test yet, but could, have an experimental proof or disproof?

Does anyone know some good sources which do cover any of these? Also it would be great to hear less-wrongers own input to these questions!