The Grudge Report was a typical military report. There was the body of the report, which contained the short discussion, conclusions, and recommendations. Then there were several appendixes that were supposed to substantiate the conclusions and recommendations made in the report. One of the appendixes was the final report of Dr. J. Allen Hynek, Project Grudge's contract astronomer. Dr. Hynek and his staff had studied 237 of the best UFO reports. They had spent several months analyzing each report. By searching through astronomical journals and checking the location of various celestial bodies, they found that some UFO's could be explained. Of the 237 reports he and his staff examined, 32 per cent could be explained astronomically. The Air Force Air Weather Service and the Air Force Cambridge Research Laboratory had sifted the reports for UFO's that might have been balloons. These two organizations had data on the flights of both the regular weather balloons and the huge, high-flying skyhooks. They wrote off 12 per cent of the 237 UFO reports under study as balloons. This left 56 per cent still unknown. By weeding out the hoaxes, the reports that were too nebulous to evaluate, and reports that could well be misidentified airplanes, Project Grudge disposed of another 33 per cent of the reports. This left 23 per cent that fell in the "unknown" category. There were more appendixes. The Rand Corporation, one of the most unpublicized yet highly competent contractors to the Air Force, looked over the reports and made the statement, "We have found nothing which would seriously controvert simple rational explanations of the various phenomena in terms of balloons, conventional aircraft, planets, meteors, bits of paper, optical illusions, practical jokers, psychopathological reporters, and the like." But Rand's comment didn't help a great deal because they didn't come up with any solutions to any of the 23 per cent unknown.