One of the things I argue in my review is that Robinson’s title is a gloss upon the book—Kepler’s Dream—that some consider the first properly science fictional novel. Although by ‘some’ perhaps I mean, well, me; which in turn many explain why I feel especially gratified by the canny intertextual eloquence with which KSR’s parses the conventions of early SF: the balance between fantastical extrapolation (in this case, futuristic extrapolation) and actual scientific observation; the mode of transport from world to world; the utopian and satiric components of the imaginary worlds encountered and so on.
Hera, a sort of 31st-century psychiatrist, shows Galileo how the raging tantrums of both his fierce old mother and his equally fierce young mistress were grounded in the situation of two intelligent individuals struck in a society that permitted women little or no options. There’s a vivid little scene of the two of them going at one another hammer-and-tongs with imprecations and actual violence, Galileo in the middle trying to separate them and feeling very sorry for himself to have been saddled with such harpy women. Back in the 31st-century Hera asks: ‘Why were they fighting?’ ‘They were angry people,’ Galielo replies. ‘Choleric. They had so much yellow bile in them that if you pinched them your fingers would turn yellow.’
‘Nonsense,’ Hera said. ‘You know better than that. They were people, just like you. Except that their lives were crimped , every day of their lives. Women in a patriarchy, what a fate. You know what I would have done if I were them? I would have killed you. I would have poisoned you or cut your throat with a kitchen knife.’Robinson’s talking about what Spinoza called conatus, of course; but glossing this as pride is a fascinating move.
‘Well.’ Galileo regarded her uneasily; she towered over him, and her massive arms were like carved ivory. ‘You said that a time’s structure of feeling has a lot to do with how we are. Maybe you would have felt differently.’
‘All humans have an equal amount of pride,’ she said. ‘No matter how much it gets crushed or battered.’
‘I don’t know if that’s true. Isn’t pride part of a structure of feeling?’
‘No. It’s part of the integrity of the organism, the urge to life. A cellular thing.’ 
I also note in my review that the 17th-Century stuff often has a roundedness that the 3020 scenes lack: the mis-en-scène is more immersive, more complete, and the characterization is much more effective. Indeed, the characterization is one of the great strengths of this novel: not only Galileo, although KSR does a tremendous job in fleshing out the historical façade of this alabaster saint of science, but in several of the figures around him. The scenes towards the end between Galileo and his daughter Maria Celeste are tremendously moving; and the scorpion’s nest sense of Rome, its networks and politics, its conspiracies, loyalties, paranoias and vendetti, is superb.
KSR gives us several of the most celebrated Galilean moments: eppur si muove is in there; the experiments with balls rolling on inclined planes; though not the weights dropped from the leaning tower of Pisa—historically apochryphal of course—and I might have wished the cameo appearance of John Milton fuller. It’s excellent, but over too soon. But one of the major achievements of this novel is to bring alive the excitement and epiphanic joy of scientific discovery. That process, working from first principles to extrapolate a profound understanding of the cosmos is also the theme of Egan’s Incandescence of course; and I don’t doubt many people feel I’ve said enough about that novel already. The point of the comparison is not that I feel KSR does a better job in Galileo’s Dream than Egan did in his novel; although actually I think he does. Egan’s approach, of course, was different: a rarified, arguably purified schematic of this process projected onto a far-future insectile species. Robinson does much more not only because he is an incomparably better stylistic than Egan (though he is); and not only because he draws much richer, more human characters (though, again he does); and not at all because he is telling a historical story and Egan details a wholly imaginary fable—that part, in fact, has nothing to do with it. The crucial thing, I’d say, is that Robinson evokes the sheer ontological thrill of scientific discovery; the trembling-on-the-lip of understanding. Egan, perhaps, takes that for granted; but by beautifully evoking the psychological ground Robinson is able to illuminate all of Galileo’s discoveries in shimmering brilliance. Here he sits ion the garden of the nunnery in which his daughter, starved by her piety, has recently died.
Galileo sat there looking at the strawberry plants at his feet. The new leaves came out of the ground neatly folded. Any new leaf was a remarkable thing when considered closely. The little plant emerged from brown mud that was granulated and unpromising. Wet dirt, nothing more. And yet there were the new leaves. Earth, water, air, the subtle fire of sunlight, driving the life into everything. Something in the mix of these, and something beyond them … For a long time he sat there staring, feeling on the edge of understanding, of seeing things clearly. The feeling swelled in him as he realized that it was an emotion he felt all the time, that his entire life had been one protracted case of presque vu. Almost seen! Almost understood! The blue sky quivered with this feeling. The 3020 scenes, despite a perfectly serviceable mystery about the nature and intentions of the life-form discovered beneath the Europan ice, never generate this intensity of affect. More, there are structural problems that are a function of the time-travel to-and-fro. When he is in the future, Galileo is educated super-rapidly, by the Marvellous Machines of the future utopia, brought up to fourth millennium levels not only in science but also history. On his many returns to Seventeenth-Century Italy he is, sometimes, given an amnesiac agent to forget this info; but sometimes he is not; and that may make up wonder why he doesn’t immediately sit down with his pen in 1630 Tuscany and write a 31st-century equivalent of The Brief History of Time. Historia Temporalis Brevis, I guess. KSR has a couple of strategies for negotiating this problem—and the main one is that most of Galileo’s important discoveries have already been made before the future-people contact him, for instance. But there are moments—when he starts observing what he thinks are ears on the planet Saturn, and wonders what they might be [318-19] is one. Given that he has, at this point, received a super-advanced education, and actually flown right round Jupiter in a transparent spacecraft (and not taken any forgetting-agent) made me think: wouldn’t he recognize planetary rings when he sees them? Wouldn’t he already know about Saturn?
I don’t mean to nitpick. In fact, it is not beyond belief that Galileo might forget what he has learned, because one of the novel’s main themes—one of Robinson’s perennial themes—is that memory is not a simple process. And I very much liked this insight: ‘He saw again that there were men who were both highly intelligent and deeply stupid.’ 
I loved the games KSR plays with psychoanalyzing his characters (‘Pride leads to a fall,’ the elderly Galileo tells a priggish young Milton. ‘You should remember that.’ But he goes on: ‘I know, I was proud. But I fell. My mother stole my eyes.’ 565) including a nifty 31st-century magic helmet that brings to life the memories with the greatest emotional charge. At the same time, I can see that other readers might not enjoy that so much; or KSR’s slightly cranky devotion to the idea that the four humours really do govern our personalities, which was one of the hobby-horses he rode (with Freud for sword and a Greimas Square for shield) in the Mars books. Still, Galileo’s mother—a splendid, rollicking portrait of a harridan—really did steal his eyes; or his telescopic lenses at any rate (she wanted to sell them to make a bit of money); and blindness, the necessary blindness of existence, connects expressively with another of KSR’s perennial fascinations, the intermittencies of memory.
At the end, it is a novel not just about doing science, but about doing good. That is what gives it its greatest profundity; the articulation of a sense in which we are all entangled with one another. The peroration with which it ends is genuinely earned by the narrative that precedes it:
And so when sometimes you feel strange, when a pang tugs you or it seems like the moment has already happened—or when you look up in the sky and are surprised by the sight of bright Jupiter between the clouds, and everything suddenly seems stuffed with a vast significance—consider that some other person somewhere is entangled with you in time, and is trying to give some push to the situation, some little help to make things better. Then put your shoulder to whatever wheel you have at hand, whatever moment you’re in, and push too! Push like Galileo pushed! And together we may crab sideways toward the good. Fine advice, that.