First edition. A memoir by the former head of Project Blue Book, the US Government's investigation into UFOs, describing the early years of the project. 320 pages.
Although there is nothing on the copyright page or elsewhere to suggest this is a later printing, the 75 cent cover price feels a tad high for 1956, given Ace Doubles were only 35 cents. So if someone has any info about this being a later printing, please feel free to add!