"[3] Swiss psychiatrist Carl G. Jung examined Angelucci's account in detail in his book, Flying Saucers: A Modern Myth of Things Seen in the Skies,[4][5] providing a comprehensive analysis spanning around ten pages.
[6] He experienced recurrent episodes of ill health, which often led to a state of total exhaustion and painful nervous prostration, sometimes requiring him to be hospitalised.
[2] One such study, performed in 1946,[7] included the release of weather balloons filled with different varieties of mould into the atmosphere in order to ascertain the effects of altitude, temperature, and air pressure on the samples.
He also described having experienced a "missing time" episode and eventually remembered living for a week in the body of "space brother" called Neptune, in a more evolved society.
Whilst living as Neptune, Angelluci reported inhabiting "the largest asteroid" of the remains of a destroyed planet, while his usual body wandered around the aircraft plant in a daze.
Angelucci was convinced that his physical frailty enabled him to have spiritual attunement, permitting extraterrestrial contact and imparting knowledge of Beings of immense benevolence.
[10] Angelucci wrote about his personal involvement with and encounters with extraterrestrials, UFOs, and higher spiritual beings in various written works[12] including published books, interviews and pamphlets.
His later works include "Son of the Sun", "UFO Contactees and Reports",[13] "The Nature of Infinite Entities",[14] "Saucers First Contacted Revealed 20th Century Times",[15] "California Soul Rush Days"[7] and "Concrete Evidence".
Angelucci wrote the first version of his theories of matter, energy and life, The Nature of Infinite Entities in 1952, based on research done earlier in Trenton, in 1946, including the launching of a giant cluster of weather balloons.
Within the book, Angelucci studies the numerous documented cases of UFO sightings and describes events that he personally experienced, providing analysis of their technological makeup, propulsion systems, and other physical properties.