What one reviewer at amazon said about Prester John:
This is a good old fashioned adventure story-- right along with lines of "King Soloman's Mines", "Allen Quartermain", "Beau Gests", "The Sea-Hawks","She", "Scaramouche","The Scarlet Pimpernel", etc.
"Prester John" is based on a character/myth of the same name. Thoughout the Middle Ages it was rumored that a priest named "Prester (Father) John" had traveled to Africa to convert the natives. But instead emassed a huge fortune and made himself king of this mysterous part of Africa. So as you can expect this story is full of lost civilizations, hidden treasures, deepest-darkest Africa, great friendship and ruthless betrayal, explorers of spooky places, tigers and lions, witch doctors, and just plan good old fashioned late-victoria adventures. And despite it being written 100 or so years ago, it is still very,very readable.
So if you just want 100% escapism, or to introduce a child to the joys (and excitement) of reading, you can't go wrong with this story...esp. at this price!
Download Prester John from Project Gutenberg
or find a hard copy