Conan Doyle is invariably linked to his most famous creation, Sherlock Holmes. The stories skyrocketed him to fame and the tales are STILL spawning new fans, more than 100 years later.
Conan Doyle wrote numerous other stories as well. Some were more of what we would call science fiction (like The Lost World, with time traveling and dinosaurs). Others were tinged with the crime / mystery sensibilities he had done so well with before.
“The Horror of the Heights” is somewhere in between. First published in the Strand in 1913, it imagines what will be found by aviators in the infancy of flight. What is seen by a pilot is discovered through the remains of a bloodied notebook found in a field.
The idea that the extraordinary narrative which has been called the Joyce-Armstrong Fragment is an elaborate practical joke evolved by some person, cursed by a perverted and sinister sense of humour, has now been abandoned by all who have examined the matter. The most macabre and imaginative of plotters would hesitate before linking his morbid fancies with the unquestioned and tragic facts which reinforce the statement. Though the assertions contained in it are amazing and even monstrous, it is none the less forcing itself upon the general intelligence that they are true, and that we must readjust our ideas to the new situation. This world of ours appears to be separated by a slight and precarious margin of safety from a most singular and unexpected danger.