By the fourth Lex Barker entry into the Tarzan series things were more or less established, and though the new adventures had become almost routine, the efficiency evidenced in the previous films was still maintained. The new additions here are a surrogate for Boy called Joey, played very well by a kid whose only film this was; and a fourth actress playing Jane, pretty Dorothy Hart. The Cold War shadow is still present in this production, with a Russian villain named Rokov (Austrian-born actor Charles Korvin), who wants to get hold of the diamonds of an African tribe. As in "Tarzan's Peril" a murder happens in the first minutes, leading to the impersonation of Lord Greystoke, Tarzan's cousin, by the villain's weak colleague (Patrick Knowles), and Jane convincing Tarzan to help them. Here Cheetah's compulsive stealing is also a main ingredient of the plot, and little Joey also plays a key role in the proceedings. Considered by some specialists as one of the best Tarzan movies, it was directed by Cy Endfield, an American left-wing filmmaker who had a promising career but when blacklisted by the House Un-American Activities Committee, he went to England in 1951, where he made television, advertisement and a few good films as "Mysterious Island", "Sands of the Kalahari" and "Zulu" before retiring and inventing the Microwriter. Possibly it was Endfield who introduced several "sleight-of-hand routines", performed on screen by Rokov, who uses them to trick gullible natives. Known as a "master of the art of micro magic", Endfield had worked in Orson Welles' Mercury Theatre. Last but not least, this is probably the only Tarzan movie to include two black-listed film professionals: Endfield and Korvin.
