The Lost World by Sir Arthur Conan Doyle (Pan, 1953)

Found on the "Vintage" table at last weekend's Lifeline Bookfair:

THE LOST WORLD, one of Sir Arthur Conan Doyle's most famous novels, is the story of four men's expedition to a remote plateau in South America, cut off from the surrounding country by unscaleable perpendicular cliffs.  Here, in an area the size of the English county of Sussex, strange creatures long extinct in the outside world have survived from prehistoric times, including the huge pterodactyl, half bat, half bird; the reptile-headed iguanodon, forty feet high; the terrifying carnivorous dinosaur; and the horrible ape-men.  The adventures of Professors Challenger and Summerlee, Lord John Roxton, and the journalist Malone are breathlessly exciting, and lead up to the climax of their return to London to confound their sceptical critics.
The idea for the tale was suggested to the author by the fossilized footprints of a prehistoric monster found near his home on the Sussex Downs; the then read Professor Ray Lankester's book on extinct animals.  He took the name of Professor Challenger from the wooden ship Sir Charles Wyville Thomson (the zoology professor whose lectures he'd attended at Edinburgh University) had dredged the seas for new forms of animal life; but he gave Challenger the black beard and booming voice of another former Edinburgh professor.  Conan Doyle enjoyed the character whom he thus created so much that he imitated him in real life, and, according to his biographer, Mr. John Dickson Carr, "made Challenger a completely uninhibited version of himself."  The Lost World, first serialized in the Strand Magazine, was an immediate success and was later filmed.

 Pan started publishing paperbacks in 1947, but this is the earliest example of their output I've found so far.    The back cover reads less like a blurb than a mini-essay!

The Lost World by Arthur Conan Doyle (John Murray, 1960)

If you take the trouble of searching the dusty shed part of The Green Shed you can find some amazing stuff:

 

On a high plateau in South America a group of explorer-scientists led by the famous Professor Challenger discovered a huge tropical marsh surviving from prehistoric times inhabited by giant reptiles and the grotesque half-ape forerunners of man.  In the face of fantastic dangers they capture one of the flying reptiles and bring it back to London, where it escapes and causes havoc.  The Lost World was the first of the full-length novels of this kind, and its breathtaking combination of science and fiction and real characters keeps it without a rival.

Everyone knows Arthur Conan Doyle as the creator of Sherlock Holmes.  Less well known are his ventures into writing science fiction and fantasy.  The Lost World (1912) is the first in a series of three novels featuring the bullish and eccentric Professor Challenger: the others being The Poison Belt (1913) an end-of-the-world story, and The Land of Mist (1926) a rather too-credulous look at the claims of spiritualism.

This first novel is literally a "lost world" story, with Professor Challenger and his band of intrepid explorers finding an isolated plateau  in South America inhabited by dinosaurs.  Evidently South America was to the average person of 1912 as outer space is today--a place where anything could happen, and strange things  could be found!