Rating: 
Summary: Background & Summary
Review: At some time or another, it seems, every s.f. writer has to do a time-travel book. I decided that I wanted to try one which at last faces up to the paradoxes and tackles them, without such cop-outs as characters religiously making sure that everything is set up and left the way it "happened," magical, mysterious forces compelling them to act in ways that keep everything consistent, masking the paradoxes by burying them far in the distant past, and that kind of thing. The other thing I wanted to do was get away from those conjurors' boxes, introduced in whatever disguise, that we read about all the time. I certainly wouldn't start by jumping hopefully into one to be launched off to who- knows-where--or, quite possibly or more probably, depending on one's degree of natural cynicism--to simply vanish without trace. I'd want to send a few monkeys or some such through first, and make sure they came back okay. In other words, if this ever became a real issue being investigated by real scientists, it seemed to me that they'd handle it very differently than as depicted in a lot of the stories we've seen. Come to think of it, if this kind of physics ever became a reality, would it be likely to emerge immediately at a sufficient level of sophistication to permit the sending and reconstitution of structured objects, or even of matter? A more plausible beginning might be the ability to send just a whiff of energy. Now, if you can send energy, you can modulate it, for example by switching it on and off according to some kind of code, which means you can send information. If you can send information, you can cause events at the other end to be changed, hence introducing all the familiar paradoxes of time travel, but perhaps in a more plausible setting. The result was THRICE UPON A TIME, which deals with a group of scientists and others trying to make sense out of experimental results derived from the discover of being able to propagate signals back through time--in other words, figuring out the rules. Obviously, I had to know the rules in order for the characters to discover them. Trying to work them out tends to be difficult when they're entangled with the complexities of plot situations. So to separate them out and simplify things, I reduced everything to a model consisting of a button and a lamp. When the button is pressed, the lamp comes on. You can't get much simpler than that. Now, add in a black box that sends the signal back through time so that the lamp comes on thirty seconds before the button is pressed. Two questions arise: (1) The lamp comes on. Thirty seconds later it's time to press the button. I won't. What happens? (2) Thirty seconds ago the lamp didn't come on, but I press the button anyway. What happens? Every time-travel paradox is a variation of one or the other of these two situations. When you can answer the above two questions, you can resolve all of them. Three hundred pages of reading about people pressing buttons and recording what lamps do would make tedious reading. Having figured out what the rules were, I built around them the kind of character and problem situations that make up a novel. They involve a swarm of microscopic black holes orbiting through the solid matter of the Earth, a lethal virus released by a meteor impact on an orbiting isolation lab, and a pair of lovers finding each other through highly improbably circumstances on one timeline, only to lose each other again when it reconstructs into something else. Outwardly, the kinds of thing that readers can care about and relate to. But beneath the camouflage, the underlying mechanics follows the same rules that apply to the buttons and lamps.
Rating: 
Summary: Hogan's Best
Review: Beware: Once you have read this book, you will
never look at time travel in other stories in
the same way.
Hogan is the master of taking
pure science, and, making some small assumptions, creating a whole new set of
theories to be explored. This book, in my opinion, is his finest effort to date.
Many science fiction stories use time travel as a plot device. Hogan's novel speculates about the very nature of time. He does this by creating a theory by which it is possible to communicate backwards through time, and explores the consequences.
I guess the thing that I like most about his writing is that he requires his readers to suspend disbelief on one or two small details, and then uses those details to create several surprising turns in the plot. When looked at from the end, these plot turns seem obvious, but the first time through it is truly surprising where the assumptions will lead.
Rating: 
Summary: No literature, no science, just fiction
Review: Fond as I usually am of Hogan's books, this one is a bore. It tells of sending a message backwards through time, and how this changes the present (the future of the past to which the message was sent), then tells it again and again. There is no depth to any of the characters. There are lots of other, good, Hogan books, go to them instead.
Rating:
Summary: A Great Story 3 Times Over!
Review: I've never been a fan of "conventional" time travel stories with ideas of parallel timelines or other ways around the famous "grandfather paradox." They've all seemed cheesy. Along comes Hogan, who looks at the paradox square in the eye, and deals with it once and for all. Foes of time travel stories won't find this one hard to follow. Hogan takes the reader along with himself, describing the 3 different histories and how they change, without losing the reader in a miasm of contradictions and scene-switches.
Rating:
Summary: A Great Story 3 Times Over!
Review: I've never been a fan of "conventional" time travel stories with ideas of parallel timelines or other ways around the famous "grandfather paradox." They've all seemed cheesy. Along comes Hogan, who looks at the paradox square in the eye, and deals with it once and for all. Foes of time travel stories won't find this one hard to follow. Hogan takes the reader along with himself, describing the 3 different histories and how they change, without losing the reader in a miasm of contradictions and scene-switches.
Rating: 
Summary: Good Read, worth visiting
Review: I've read this book twice. Once when I was younger, and again recently. It was what I would consider a Good book. Hogan always seems to turn out an entertaining book, a book worth reading, but not a Snow Crash. I could read this book again when its turn comes up. Worth buying and reading.
Rating:
Summary: Hogan at his very best!
Review: James P. Hogan's best works have always been about science and scientists exploring the universe, finding out how it ticks, and being surprised not so much by what they find as by the byproducts of what they find. In this story, a machine which can send signals back in time is invented, and the rest of the story revolves around three key questions: "Exactly how does it work?", "What does it mean about the way the universe works?", and finally, "How do we use it wisely?" Hogan's characters quickly became friends, and I got thoroughly caught up in their quest for answers, some of which, as you would expect, are kept secret until right up to the very end, which includes one of the most gorgeous juxtapositions of "Surprise!" with "Of course!" I've ever read. This one was more than worth the time spent reading it.
Rating:
Summary: This is a terrible book. Skip it.
Review: Mankind, through stupidity and misuse of science has destroyed the world. Hogan gives this hackneyed and, unfortunately, nearly ubiquitous science fiction premise only a slight spin by contriving a story in which Man wipes himself out not merely once but twice simultaneously. The "science" in this science fiction story is not true speculation but Star Trek style technobabble. The "characters" are wooden puppets carried along by annoying, cliche-filled naturalistic dialog. The "dramatization" appears to have been edited out and replaced by long-winded, repititious exposition. There is virtually no sign of a plot for at least the first 100 pages. The plot, such that it exists, would be nearly invisible were it not for the frequent diversions into totally irrelevant, meaningless patches of dialog that seem to go on for pages at a time. This story might have made a passable novelette or short-novella, but at novel length it is too much to bear.
Rating:
Summary: This is a terrible book. Skip it.
Review: Mankind, through stupidity and misuse of science has destroyed the world. Hogan gives this hackneyed and, unfortunately, nearly ubiquitous science fiction premise only a slight spin by contriving a story in which Man wipes himself out not merely once but twice simultaneously. The "science" in this science fiction story is not true speculation but Star Trek style technobabble. The "characters" are wooden puppets carried along by annoying, cliche-filled naturalistic dialog. The "dramatization" appears to have been edited out and replaced by long-winded, repititious exposition. There is virtually no sign of a plot for at least the first 100 pages. The plot, such that it exists, would be nearly invisible were it not for the frequent diversions into totally irrelevant, meaningless patches of dialog that seem to go on for pages at a time. This story might have made a passable novelette or short-novella, but at novel length it is too much to bear.
Rating:
Summary: Idea-driven SF
Review: One of the things I like about James P. Hogan's fiction is that it's so largely idea-driven. He makes plausible projections from present-day science and uses them as the basis for a story (which generally includes the story of the discovery of the scientific principles at issue). This is one of my favorites. In it, Hogan explores a mind-blowingly cool scientific concept: what if it were possible for information to travel from the future to the past? "Classic" SF treatments of time-travel themes leave something to be desired -- even Robert A. Heinlein's fine short story "By His Bootstraps," which depends for its success on several narrative tricks that work in the story but aren't very realistic elsewhere. (The protagonist has to relive the same series of events several times, from different points of view, without really being able to _make decisions_ as this happens.) Others allow the possibility of changing the past but allege that _actually_ changing it would somehow make the universe go blooey. A few allow the past actually to be changed but don't explain how it's possible (in particular ducking the obvious paradoxes). So Hogan started from scratch and tried to provide a plausible scientific basis for his own tale. And what he came up with was a way that information from the future _can_ change the past -- with, let's say, _very_ interesting consequences for his characters, including a host of brand new moral problems and hard choices. As I suggested above, the story is (like most "hard" SF) fundamentally idea-driven rather than character-driven, but Hogan's characters are believable and interesting all the same. If you enjoy this sort of thing, you'll also want to read his later novel _Paths To Otherwhere_ for exploration of the Many Worlds Interpretation of quantum mechanics. And check out _The Proteus Operation_ for yet another fascinating twist on the time-travel/changing-the-past theme.
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