FLYING SAUCERS UNCENSORED by Harold T. Wilkins

A swath of sightings from around the world, courtesy Wilkins' formidable army of correspondents. Many occupant encounters and hostile interactions. According to a deleted Amazon review this also features "the first mention in a UFO book of the alleged encounter that President Eisenhower had in 1954 concerning a visit to Edwards AFB," now a pillar of the modern UFO conspiracy matrix. Available to read and download at archive dot org.

Pyramid Books, 1967 (original pub. 1955)