Tarzan and the Lion Man was published in 1934 and is partly a satire of the Hollywood film industry that had been making Tarzan movies for over twenty years by that point. A film production company called the BO Studios has come to Africa to shoot a Tarzan-style jungle adventure starring an actor named Stanley Obroski, who looks remarkably similar to Tarzan. Burroughs is having fun with the doppelganger premise and with the artificiality of film-jungle production in real African conditions.
The expedition gets lost in a remote region populated by intelligent gorillas descended from a previously unmentioned experimental program. The gorilla city of Alemtejo is ruled by King Henry the Eighth, an extremely literal-minded gorilla who believes himself to be the actual sixteenth-century English king. The book is genuinely funny in places, possibly the most consistently comedic Tarzan novel. Tarzan and Obroski’s resemblance becomes a major plot point. A welcome change of tone in the middle of the late-Burroughs run.