Donald Zygutis claims to be "the world's foremost authority on Carl Sagan's ET beliefs, particularly his work on ancient alienism". He asserts that NASA tried to keep this secret, apparently because they were in favour of trying to detect signals from distant planets using radio telescopes, and they were sure that interstellar space flight was impossible.
One of the main problems with this book is that the reader is never sure that the ideas and beliefs of scientists mentioned are true, or are merely guesswork by the author. This means that we are left unsure of the tensions between those who believe that interstellar travel is not a practical possibility, and disapproved of Sagan's interest in attempting to find evidence of visits by aliens. Zygutis asserts that Sagan believed that we have received such visit, but most people interested in such matters would no doubt agree that he was merely interested in it as a possibility. In fact, Zygutis assures us that Sagan had no time for UFO reports, dismissing them as unreliable.
This is presumably meant to assure us that Sagan was no crank and that his speculations about space aliens should be taken seriously. There are other scientists who take the possibility of technically advanced aliens sriously but they do not claim to have evidence that they have visited Earth. It seems to be assumed that, if they exist, they are too remote from us for their activities to be detected.
Zygutis complains that scientists refused to take Sagan's consideration of the possibility of visits by aliens in the distant past seriously and that clues could be found in ancient writings. We are given, of course, the example of the rise of the Sumerian civilisation and the writings of the Greek historian Berosus on the history and culture of ancient Babylonia, including the legend of Oannes, a mysterious creature who instructed the people in a wide range of subjects during the day and spent the nights in the sea, as he was amphibious.
The implication here, of course, is that Oannes had come from some distant planet. When I first read about this character some years ago I was rather amused by thinking of Oannes and the other occupants of his interstellar spacecraft sloshing around in water and wondering how they avoided short-circuiting the gadgets that one might expect to find in a spacecraft.
Zygutis repeatedly states that Sagan has produced scientific work showing that aliens have visited Earth and interacted with people, and that he believes that they really exist. However, if you actually read what he has written you will realise that Sagan was rather cautious and presents his findings as possibilities. In his mentions of some ancient writings he obviously realised that it was a good idea not to interpret them too literally.
The practice of reaching sensational conclusions by ignoring the interpretations of ancient writings by scholars who engage in serious study of them is one of the techniques used by the writers of sensationalist books about ancient astronauts. This causes most serious writers to ignore them, if only to avoid being tarred by the same brush.
Zygutis does make some good points about professional sceptics who sneer at everything that they don't believe or is not to their taste, but too many of his comments about their beliefs and motives are based on speculation or misinterpretations of their published opinions.
His complaint that Sagan's speculations, using statistical methods, concerning the possibility of space travelling aliens in the galaxy (usually known as the 'Stanford Paper') received few comments by other scientists is not really valid, as there is not much to add to it, as his arguments are based on possibilities rather than established facts. I found the Zygutis's style of writing rather confusing and repetitious, and a much shorter version would have been more suitable. -- John Harney