The film has frequently been compared with Otto Preminger's 'Bunny Lake is Missing' (1965) and the slightly later picture 'Don't look Now' (1973) from director Nicolas Roeg.
The name of the espionage agency was ''The Organization''.
The literal English translation of the film's original French title ''La Maison Sous Les Arbes'' translates into the English language as ''Home Under The Trees'' or "The House Under the Trees".
Many American movie posters for the film were headlined by a quote from famed film critic Rex Reed. The text preamble stated: ''Rene Clement, the French Alfred Hitchcock, has sculptured a masterwork of suspense and human emotions that put sweat on my palms and kept it there." - Rex Reed, syndicated columnist''.
The film was selected to screen out of competition at the Cannes Film Festival in 1971.