Kim Stanley Robinson is one of my favourite storytellers, stretching from Californian light to Mars explorations, and he does not disappoint, this time. The book travels a difficult terrain for a sf writer, the historical novel, but there, Robinson excels, giving Galileo flesh and blood, a very good (and possibly quite accurate) portrait. The weakest parts of the book are actually the sf parts, although they do serve their main function of dragging Galileo into a wider debate on enlightenment and democratization. What if Galileo had been burned at the stake? The threat was very real. The world could have been much more religious-dogmatic than it became. Robinson’s speculations here are high value even if his sci-fi concept is a bit thin. This is a good historical novel “plus”.