In Edgar Rice Burroughs: Master of Adventure, author Richard A. Lupoff suggests that Tarzan and the Jewels of Opar may be considered the last novel in the original Tarzan chronology. He states, “The quality is not very great, the plot is still a continuation of the original elements introduced in earlier books.”
Based on this warning, and my displeasure with the fourth Tarzan novel, The Son of Tarzan, I'm not sure why I pursued the series more. Partially, I was hoping that this novel would have a bit of fantasy or sci-fi elements in providing more emphasis on Opar and Tarzan's presence there. But, I quickly learned that isn't the case. This is another chase-the-chaser that is chasing Jane and her kidnapper.
In this novel, Tarzan's investments have dwindled and he needs more capital. He journeys back to the city of Opar to steal gold. While there, he is knocked unconscious by a boulder and awakens with amnesia. This leaves him roaming the jungle in a primitive state similar to his boyhood. Only he says silly things repeatedly like “pretty pebbles”. He also denies Opar's high-priestess La once again. She's in love with Tarzan and he wants nothing to do with her. At this point she's one of the few characters that can successfully remain in one place for five books. I'm just saying...I would at least entertain the decision.
Meanwhile, Burroughs has to have Jane kidnapped. It's apparently what his readers desire in every Tarzan novel. So, Jane is captured this time by ivory and slave traders led by Achmet Zek. Thrown into the mix is a disgraced Belgian officer named Albert Werper. He spends his time attempting to grab a bag of jewels – pretty pebbles – from whoever and whatever chapter they are in.
The narrative is like the old film It's a Mad, Mad, Mad, Mad, World. People chasing people who are chasing money. Werper chases the jewels, Tarzan chases the jewels, La chases Tarzan, Mugambi chases Tarzan and Jane, and the slave traders chase after the Opar gold, the pretty pebbles, and the reader's attention – which is in serious jeopardy if you make it to page 100. None of this would be dull and lifeless if Burroughs didn't recycle the plot. But, he does and this is an absolute mess.
Seriously, just skip this book and jump ahead to Tarzan the Untamed and its military-themed narrative amidst World War I.