This book is an authentic reproduction of the original printed text in shades of gray and may contain minor errors. Despite the fact that we have attempted to accurately maintain the integrity of the original work, the present reproduction may have minor errors beyond our control like: missing and blurred pages, poor pictures and markings. Because this book is culturally important, we have made available as part of our commitment to protect, preserve and promote knowledge in the world. 'This title was originally published in 1963. Donald Howard Menzel (April 11, 1901 – December 14, 1976) was one of the first theoretical astronomers and astrophysicists in the United States. He discovered the physical properties of the solar chromosphere, the chemistry of stars, the atmosphere of Mars, and the nature of gaseous nebulae.The minor planet1967 Menzel was named in his honor, as well as a small lunar crater located in the southeast of Mare Tranquilitatis, the Sea of Tranquility. In 1968, Menzel testified before the U.S. House Committee on Science and Astronautics - Symposium on UFOs, stating that he considered all UFO sightings to have natural explanations. Despite the fact of all Menzel's scientific backgroung, he fell short in explaining the UFO phenomena. Copy and paste the link for our books: https://saucerianbooks.blogspot.com/ Table of Contents: THE SAUCER WORLDS UFO Reports and the Air Force-The Scientist's View-The Question of "Evidence"-Various Types of UFO-Descriptions of UFOs-A "Baedeker's Guide" to Saucerdom Arnold's Nine Disks-The Great Shaver Mystery-The Maury Island Fragments-Science Fiction Adopts the Saucers-Mirage or Wave Clouds? AIR-BORNE UFOS: BALLOONS TO BUBBLES The Mantell Tragedy-A Probable Solution of the Mantell Case- A Radiosonde over Virginia-Skyhook and Pibal UFOs-The Guantanamo "Dogfight"-The Wallops Island UFO-Weather Balloons and Saucers-Plastic UFOs and the "Stack of Coins"- Jets and Contrails-The Killian Case- . . . And Kites and Soap Bubbles A Mirage of Sirius-Earth's Distorting Atmosphere-The "Whipping