The log book of a doctor assigned to Operations Crossroads, the atom bomb tests at Bikini, this is an unpretentious, day-by-day record of that experiment, the steps taken to protect the personnel from invisible dangers of radioactivity, to determine the damage to living tissue. The trip out, the briefings prior to the dress rehearsal, finally ""Able Day"" when the bomb was released; the various tests to determine the plutonium contamination above and below water, and finally the abandonment of the target fleet, after the lingering and insidious nature of the radioactive agent had been proved.... Documentary value.