As expected from Haldeman, technically excellent book.
One way the tale may be described is as follows: Humanity discovers two 'techonologies', a 'translation' mechanism that makes possible the exploration & colonization of distant planets, and an alien organism that acts as a 'mindbridge' and pushes humanity onto the path of telepathic communication. Both discoveries are detailed out with numerous complications, each comes with its deadly and inconvenient caveats.
As a result of the Levant-Meyer transition and the mindbridge, humanity is able to meet and communicate with an alien race, the L'vrai, of shocking capabilities and mentality, and this encounter is detailed in the later parts of the book.
The description of the discovery of the Levant-Meyer translation, in terms of an accidental finding by a scientist doing a totally unrelated experiment, is a retelling of a story that has been true in many scientific discoveries. (Even has a name: Serendipitous.) The idea that humans went on using the effect, perfecting it by trial and error, but not having a theoretical grasp of why it works, is a bit harder to swallow but not totally implausible. (Being a theoretical physicist myself, I would imagine that the appearance of such an effect would lead to thousands of theorists pouncing on the problem like a pack of wolves.. of course it is totally possible that they might not be able to properly understand the effect for a long time.)
The description of Lefavre's father's scientific rise and fall, with a refutation quickly disproved, is quite cute -- and realistic. Many talks at the American Physical Society have created fame and infamy for the speakers as they claim to refute, prove, disprove theories and conjectures.
The description of the use of the Translation effect, its exploitation by money-making companies, and the highly inconvenient 'slingshot' caveat, are narrated well. The chapter detailing an advertisement is an unusual and quite effective narration style.
The second technology, the "Mindbridge", is explained with some imagination -- to be a complete mystery for two centuries, until it is found that the bridges were built as part of an elaborate game by a godlike race that existed a million years ago, on some distant planet.
This tale is told in an irregular chapter --- a flash-forward to the future. The hints in this chapter, of many wonders to come, of our descendents overcoming many barriers and possessing telepathic abilities, provides a feel-good optimistic vision. On the other hand, the flash-forward is too short -- it would be nice to know a little bit more about our future voyages to the stars!
The social vision of Jacques Lefavre's own times are not quite so hunky-dory, and has its gloomy ominous aspects, which seems more typical Haldeman. The company which in principle you can leave any time you want, but in practice you are bound to by the threat of poverty, reminds us of the sinister multinationals of today -- these multinational companies have the world in a much tighter deadly grip than they did in Haldeman's time forty years ago. Some of Haldeman's dark visions have unfortunately come true.
Like many other White writers, Haldeman's vision of the future involves mainly the white world, although there is the token chinese and the token black. Today's Third World is absent from the picture. This could mean two things -- either, the Third World has continued to wallow in poverty and the White world has managed to keep 4-fifths of the world's population confined to the peripheral status that they are in today, or, that the White world has somehow managed to do away completely with those inconvenient people already.
Granted, this is a feature common to most white SF writers (exception: Ursula LeGuin), and JH in fact deserves some credit for each of his two nonwhite characters.
For the Chinese character,I appreciated the fact that he is speaking and thinking in Chinese, i.e., Chinese still exists and the world does not all speak English. (Not all white SF authors are as merciful in their visions of their future; in particular, American authors often seem to be so uncomfortable with the existence of all those alien languages that they often quickly postulate that the World's people will all soon speak English.)
For the black female character, I appreciated the fact she was at least partly African, had a good African name unpronouncible to Jacques, and was not blackAmerican or similarly 'tamed' by the white man.
Haldeman's treatment of his secondary characters is methodical but not particularly good. I did not get to care about the team-leader of Lefavre's group (Tania), and I wasn't emotionally moved by her death. The sudden deaths in the book would have been more jarring and effective if we cared a bit more about the characters. Carol, Lefavre's mate/wife appears to be a person the reader might have liked if the author had done her more justice. The idea of Carol's living on in Jacques' head, after her death, had little emotional appeal to me since I did not care much about her in the first place.
More praiseworthy is the way the author introduces us to Lefavre himself, his brutality and humanness together, so that we know him as an unpleasant person but do not dislike him. (But perhaps don't care too much about him either.) His characterization is somehow central to the story -- it is his unpleasantness (according to the L'vrai, his "animal-ness") that allow the L'vrai to communicate through him. Again, this characterization was technically adequate but not quite masterly.
In summary, despite its shortcomings, a book well worth reading if you're a SF fan.