"One of the greatest problems investigators face when dealing with the UFO phenomenon is the accuracy of what witnesses say happened. Their descriptions are subject to misperception and bias; their memories are fallible; their honesty may be suspect; their motives may be self-serving." The above is a quote from the foreword to Dr. Ellen Crystall's book "Silent Invasion" and was written by Mr. Philip Imbrogno, the author of "Night Siege - The Hudson Valley UFO Sightings.