j. malcolm farce. -- garcia. thank you very much. >> you've been watching booktv on c-span2. every weekend we bring you 48 hours of nonfiction books, public affairs, history, and biography saturday morning at 8:00 through monday at 8:00 am eastern. ... >> first off, david donovan, and secondly, michael call breeze. mr. call breeze, what is a spectrum? >> guest: well, much more commonly known as the public airwaves. it's really not a tangible thing at all, but the electromagnetic properties of the earth's atmosphere which allow the transmission of radio waves, and we call it the spectrum because it's a spectrum of frequencies that can carry, you know, basically different waves with different propagation characteristics. so some are high-frequent went si waves that carry a lot of information but not through walls or trees or over very long distances, and then there are low frequency bands such as those used by television which are considered the beach front, the very best, because those frequencies carry radio signals, you know, through multiple walls, through trees and in rura