This is the sequel to Hogan’s Inherit the Stars and builds on the ideas of the first book, or fleshes them out rather.
   It opens in a similar way too: in Inherit… a body is found on the Moon, apparently human but fifty-thousand years old; here, what’s found is a crashed spaceship, preserved in the ice beneath the surface of Jupiter’s largest moon Ganymede—but far older, twenty-five million years old this time. As a scientific team from Earth cut their way in and explore its interior, they find a device which emits pulses of gravity waves and may be some sort of beacon (marker beacon? distress beacon?). Whatever it is, they seem to have unwittingly set it off.
   This was published in 1978, around the same time that Ridley Scott’s Alien was being made, and I’ve no idea whether either influenced the other or whether, as ideas sometimes seem to be, the “crashed starship-beacon-aliens” idea was just sort of in the air at the end of the ’70s. Either way (as you can tell from the book’s title) what the humans are confronted with in this case is no nightmare.
   As with the first book, this has an old-fashioned feel to it (nothing wrong with that either; all I mean is that it took me back to when I was growing up reading Asimov, say, or Arthur C Clarke); and, again, there’s no action-packed plot, while the ideas the scientists grapple with are both a bit convoluted and scientifically unlikely. But, as with Inherit the Stars, it’s an enjoyable read nonetheless. ( )

A rare book in which pretty much nothing ever happens. I could read a dozen sentences and pass out as if I were listening to an Obama speech. ( )

My second book by Hogan

James Hogan's books are slow moving but interesting. He creates mysteries which slowly unfold for the reader. The characters are realistic but their interaction is often boring. The desire to lean about the true origins of man, the ancient history of the solar system and alien technology keeps you reading.

This is the follow up to "Inherit the Stars". Good enough that I will read the third in sequel. ( )

Seguito diretto de "lo scheletro impossibile" il romanzo si focalizza sull'apparizione nel sistema solare della nave ganiana sbucata da un lungo viaggio relativistico di oltre 25 milioni di anni (25 anni di tempo soggettivo). Grande emozione e scalpore per il primo incontro con alieni, il romanzo si dipana fra buonismo, "positivismo", curiosità e buone intenzioni, oltrechè sulla lunga serie di teorie e speculazioni scientifiche che caratterizzano questa serie.
Molto avvincente, ben scritto, teorie affascinanti (per quanto bizzarre), una bella lettura. Consigliato. ( )

Pure Science Fiction. Hier gibt es Wissenschaftler, wissenschaftliche Probleme und das intellektuelle Wechselspiel von Theorie und Gegentheorie, wie man es nur in der Science Fiction finden kann. (Isaac Asimov) ( )