His earliest ufological book, Operation Trojan Horse was one of the first books which freed ufology from the straightjacket of the ETH. His work has been a major influence of the development of MUFOB/Magonia's outlook on ufology, although it produced radically different views from two of the early MUFOB team, myself and Alan Sharp. By coincidence I recently put these comments into our archive:
Keel was perhaps the closest heir to Charles Fort, his writings being a mix of observational notes and wild speculation, which often confused and irritated 'serious' (particularly American) ufologists. However any newspaper obits will probably concentrate on the one part of his work which made it to the big screen, The Mothman Prophecies, with Richard Gere as a Keel-like paranormal investigator. The book itself, like much of his writing, was as much about the strangeness of rural and small-town America as it was about unidentified creatures. His series of articles in Flying Saucer Review, 'From My Ohio Valley Notebook' presented views across a very strange landscape.
Back in the days of MUFOB Keel was a semi-regular correspondent and I will try to get some of his letters on-line in the near future.