The current consensus concerning the abundance of extraterrestrial life is that it exists in abundance in the Universe. We have heard the accumulating data to that effect in the previous sessions, along with some skepticism. Accepting this consensus, we then ask "how do we best proceed to detect these other civilizations?" An answer to this question has now existed for several decades: we should search for radio transmissions from these civilizations. But we accept that answer with a modicum of uncertainty and unease. We worry that we do not know enough about what the future of technology may hold for the typical civilizations. We worry that this answer has been unduly influenced by our booming expertise in radio technology. We worry that even if radio is the right answer, the radio transmissions of advanced civilizations may be in a form or at a radio frequency we have not thought to search for. All of these worries must be heeded, and we must constantly reexamine our thinking to ensure that we have done the best possible job in designing the searches for other civilizations. That is what this session is about.
Here we will ask questions such as: "what are the most promising stars to look for?" The numbers of stars and radio frequencies are so great that any guidance that would lead us to more promising stars or to eliminate some as candidates would greatly reduce the required search time and expense. We ask, once again, the important question: "are there other plausible technical activities of advanced civilizations that we should surely search for?" We review the evolving argument which still leads us to believe that radio searches are the most promising approach for our civilization. We hear the present wisdom leading to a plan for the first extensive, highly organized and developed search for other civilizations, the one being prepared jointly by NASA Centers. This approach is very promising, and its mere existence and the support it is receiving from important governmental figures and bodies is very encouraging. We also hear what our Earth might look like to a distant radio telescope. This gives us some guidance and insight as to the form in which signals might be falling on Earth.