Purchase one of 1st World Library's Classic Books and help support our free internet library of downloadable eBooks. Visit us online at www.1stWorldLibrary.ORG - - "The mere existence of some yet unidentified flying objects necessitates a constant vigilance on the part of Project 'Saucer' personnel, and on the part of the civilian population. "Answers have been - and will be - drawn from such factors as guided missile research activity, balloons, astronomical phenomena. . . . But there are still question marks. "Possibilities that the saucers are foreign aircraft have also been considered. . . . But observations based on nuclear power plant research in this country label as 'highly improbable' the existence on Earth of engines small enough to have Powered the saucers.