This is a collection of ebooks written by the author, John Keel. All files are in PDF format. 

Contents:

Jadoo (1957)
Our Haunted Planet (1971)
The Mothman Prophecies (1975)
The Cosmic Question (1978) [Reprinted edition of The Eighth Tower]
Disneyland of the Gods (1988)
The Complete Guide to Mysterious Beings (1994)
Operation Trojanhorse (1996) [Reprinted edition of 1970 original]

Articles:
The Man who Invented Flying Saucers
The Cape May Incident


All credit goes to the original uploaders, I'm just sharing here :)