Book review: The Cryptoterresterials by Mac Tonnies

I first came across Mac Tonnies in a volume of the excellent Darklore series, which included his "The Ancients Are Watching", a piece on the possibility that the UFO phenomena represents an interaction with a post biological intelligence. In this essay, he mentioned in passing another theory that an impoverished culture of indigenous humanoids could be behind UFOs. This idea really piqued my curiosity as I've had a long term interest in things like The Shaver Mystery,  the notion of an earth based origin for UFOs (beyond secret military technology etc) had largely fallen out of fashion since the 60/70s and was intrigued to see it framed in more modern terms.
So it was with much anticipation, and a degree of sadness (Tonnies passed away in his sleep last October, he was only 34) that I approached this book. His basic idea is that if we look at close encounter narratives, the UFO occupants are very human like, suspiciously so for apparent extraterrestrials. Also, given the apparent degree of interest in our DNA and reproductive systems, this raises red flag in the sense that we are unlikely to be biologically compatible with extraterrestrials (if we can't reproduce with close relatives such as chimps, the chances of reproducing with aliens would be even less), yet there are cases of humans allegedly having sex with UFO occupants (the best known probably being that of Antonio Villas Boas), which if true, would point to them being more or less human. Also, there seems to be staged aspect to many close encounters, like the UFO occupants want to be seen and want us to believe they're from out there.
So from this, he theorises that we may have a sister species living amongst us, perhaps under the sea (there is a large body of sights of UFOs exiting or entering bodies of water), underground or even in remote parts of the planet. Similar ideas have been advanced in the past, notably by the likes of John Keel (though he did ultimately formulate the idea of ultraterresterials, prior to that he noted that many UFO occupants appeared very human, with long fingers, pointed chins, high cheek bones and slanted eyes being a recurring feature), what's novel in Tonnies' theory is that they may well be exaggerating their technological prowess in an attempt to maintain the charade that they're aliens and so keep us off their trail, but ultimately may represent a species in decline.
In one sense, the book works well as a critique of the Extraterresterial Hypothesis (ETH), which is the dominant explanation for the phenomena (beyond the null hypothesis, which is that it's all hoaxes, misperceptions and novel psychological phenomena). There's no evidence at all of an extraterrestrial origin, beyond claims of the entities themselves and our own cultural assumptions, and 63 years on from Kenneth Arnold's seminal sighting over Mt Rainer, we're no closer to an answer, so maybe we should be looking elsewhere?
The logic of the Cryptoterresterial Hypothesis is fairly strong, however it's weak point is firm evidence to back it up- if scientists can detect fossil remains of ancient bacteria, you would expect a humanoid race to leave more traces, especially one with a degree of technology, and the book doesn't tackle this aspect, though it does point to areas for research, such as the fossil record, unusual artifacts, unexplained transmissions or energy emissions, the forensic aspect of close encounters and so on. I would have liked to have seen some discuss what's out there that could support this idea. Frustratingly, he had mentioned during a interview on a podcast that he'd seen US military documents relating to encounters with humanoids on a Pacific island during WW2, but none of this is included in the book.Also, he cites some fascinating first hand correspondence he's had from a man who claimed he'd had an encounter with small human-like beings that pre-date us, but now live amongst us, passing themselves off as children and homeless people, but the details of this are frustratingly brief.
Of course, it should be pointed out that this book was released after Tonnies death, and was taken from a draft he had given to a friend, so had things worked out differently, the book may have been fleshed out a bit.
What endeared Tonnies to so many was not only his endless stream of ideas (and you'll find more ideas packed into a page on this book than you'd find in the whole of some writers output), was his lack of dogmatism- he's came up with this theory, has put forward how to test it, and was more than willing to be proved wrong, which is refreshing in this field where there are so many defenders of the faith, who'll stick by theories or cases when there's no credibility left in them.
Tonnies use of language makes the book a joy to read, even if you're extremely skeptical and I suspect some of the ideas put forward in the book may well be lifted by SF writers in the future.One note I'd make is that it's probably not for people unfamiliar with the field as it discusses cases and concepts with little exposition, so if that is the case, I recommend reading a few more general books before tackling this one.
So, all in, a thought provoking book that's a great read, even if the central theory may not ultimately hold up.
If you're interested in finding out more about the CTH, this interview with Tonnies is a good starting point.