Tarzan and the Castaways was published in 1965 as a posthumous collection gathering three short pieces Burroughs had written across the 1940s. The title novella, originally The Quest of Tarzan, involves a shipwreck on a Pacific island, Tarzan organizing the survivors, and a series of conflicts with the indigenous islanders. The story is shorter and more action-focused than most of the late novels.
The second piece, Tarzan and the Champion, is a comedic novella in which a self-promoting American boxer named One-Punch Mullargan comes to Africa to publicize his career by hunting big game and ends up running into Tarzan. Burroughs uses Mullargan as a vehicle for satirizing celebrity sport culture. The third, Tarzan and the Jungle Murders, is a brisk mystery story involving the death of an aviator and a hunt for the killer. Together the three pieces make a reasonable late-Burroughs sampler. None of them is essential, but they give a sense of how the series might have continued if Burroughs had lived longer.