Fifty years ago next month, invitation-only audiences gathered in specially equipped Cinerama theaters in Washington, New York and Los Angeles to preview a widescreen epic that director Stanley Kubrick had been working on for four years. Conceived in collaboration with the science-fiction writer Arthur C. Clarke, “2001: A Space Odyssey” was way over budget, and Hollywood rumor held that MGM had essentially bet the studio on the project.

The film’s previews were an unmitigated disaster. Its story line encompassed an exceptional...