Greenland, phantom targets in, 166 Griffis Air Force Base, 68 Guantánamo Bay, Cuba, 42–44 Gulf of Mexico, 5–6, 182 Gulliver, L., 172 H Hamilton Air Force Base, 46 Hanford, Wash., 135 Harvard College Observatory, 111, 113, 175 Height-finding radar, 153, 156, 162, 163 Herget, P., 67 Hermanas, N.M., 47 _Hidden World_, 25 Hoax, Ilha dos Amores, 206; Maury Island, 21–23; Schmidt, 183; Scoutmaster, 136–37; Shaver, 17–21 Hoaxes, 198–99, 219; photographic, 203–7, Pls. VIa, VIb, 213–16; UFO, 199 Humidity, inversions of, 151, 157–58 Hynek, J. A., 37, 108, 111, 113, 127, 141, 273 I Ice crystals, radar echoes from, 71, 164; sundogs from, 244, 247 Ices, vaporizing, 94 Icy cometoid, 90, 98, 101 Ilha dos Amores, 206 Inertia, law of, 194–95 Inference, distinguished from observation, 5–6, 74; limitations of, 4–5 Insects, radar echoes from, 164–65 Institute of Meteoritics, 93, 102, 175 Intelligence, apparent control of UFOs by, 61, 80, 110, 168, 259 Intercontinental ballistic missiles, meteors as possible, 105; radar angels as possible, 166 Interplanetary travel, 19, 77–78, 216–17. _See also_ Spacecraft Inversions, moisture, 157–58; temperature, 65, 253–54, 269 Investigations, Congressional, 227, 277–78, 279 Investigators, Air Force, 271–75; civilian, 275–77 Invisible UFOs, reports of, 145, 152, 155, 165, 193, 202 Ionization, defined, 194; angel hair produced by, 221; radio interference by, 92, 178, 185, 187, 189 J James, R. L., 152, 156 Japan, UFOs reported from, 73–75 Jessup, M. K., 10, 16 Jet planes, UFO reports based on, 50, 51, 52–56, 251 Johannesburg, South Africa, 51 Jupiter, mirages of, 81–85, 141–42; seen through jet trail, 85–86 K Kearney, Nebr., 183 Kentucky, UFO over, 58, Pl. IIb Keyhoe, D. E., 10, 16, 69, 159, 276, 277 Killian case, 52–56 Kinross case, 154 Kites, UFO reports based on, 56–57, Pl. IIa Korea, UFO reports from, 73–75 Khrushchev, 166, 235 Kuiper, G. P., 230 L “Landings” of spacecraft, 180, 183–85, 203–4, 239 La Paz, L., 93, 102, 175 Laputa, 172 Las Cruces, N.M., 267 Lemuria, 10, 17, 18, 200 Lens, defects in photographic, 123, 248, Pls. VIIIa, VIIIb; of air, 63, 83, 255 Leonid meteors, 90, 92 Levelland, Tex., UFOs, 174–76, 179 Liddell, U., 31 _Life_ magazine, 95, 129, 134, 259, 268 Life, possibility of extraterrestrial, 4, 216–17, 269 Light, deflection of, 194; refraction of, 63–66; velocity of, 19, 150 Lightning, ball, 176–80, Pl. Vb; pinched, 177, Pl. Va; types of, 177 Lights, Lubbock, 123–27; reflections of, 127; unfamiliar, 52–56, 240–41, 250–52; rotating, 73–75 Lincoln, Nebr., 178 “Little Men,” 199, 220 Lock Raven Dam, 180 Logical defect, in UFO beliefs, 143 _Look_ magazine, 134, 210, 259 Lorenzen, C., 181, 235, 236