Edgar Rice Burroughs did not think of this work as literature, but more as entertainment, or escapism. I think you have to read it that way in order to enjoy it. It’s is full of statements that in today’s culture seem quaint at best, racist at worst. But like Huck Finn before him, Tarzan is a product of his time. That Burroughs believed in the superiority of the white race was not uncommon in that day—it was probably the norm.
I think that the continued appeal of Tarzan is twofold: 1) Like Huck Finn, Tarzan blazes his own trail & is a friend to the down-trodden, and 2) Like Daniel Boone, Davy Crockett,, Hawkeye, and even Superman, Tarzan is a hero who fully embodies all that Western culture wants in its men.
That the book was written with a sequel in mind is of no doubt to me. It ends abruptly and “unfinished.” The pace of the book is fast, slow & fast. The pages fly by at the beginning, but it sort of drags in the middle, until the Europeans show up.
I have a soft spot for Tarzan. In the fourth grade I was in the slow readers class. I stumbled on the Ballentine series of Tarzan books and my friend and I read our way out of that class. Between us we probably had 12 of the 24 books & traded them back & forth. Great reading & fun!
Among my favorites, besides the original volume are: Tarzan and the Lost Empire, Tarzan the Untamed, Tarzan and the Golden Lion, and Tarzan and the Jewels of Opar.