Even when it comes to fighting a genocidal enemy making relentless gains in a campaign to destroy humanity, scientists and the armed forces have a hard time seeing eye to eye, let alone working shoulder to shoulder.
A conflict of interests between the military and the brains they need to beat back the alien Fallers is among the main themes Nancy Kress develops in 'Probability Sun', the sequel to 'Probability Moon' (Tor Books, 2000; reviewed here on September 1).

To a prudent reception from the peaceable natives of World, two of the scientists Kress introduces in the first part of her trilogy return three years later to this planet remote in the inhabited space known to humankind, again aboard a vessel of the Solar Alliance navy. The military aim of the mission, once more, is to learn whether an alien artefact left by a vanished race can help win the war against the Fallers.
Now the team includes the most brilliant physicist of the day, Dr Tom Capelo, whose scientific gift is matched only by an angry, embittered outlook on life which makes him singularly difficult for anybody else to get along with, apart from his beloved daughters.
Other new characters include Lyle Kaufman, the reluctant career soldier tasked with keeping the mission together to fulfil its task, and the gene-modified Marbet Grant, often shunned by ordinary people because as a 'Sensitive', she can read too much from minute facial details and body language for comfort.
Marbet's needed to ensure good relations with the locals, given the real purpose of the team's visit to the radioactive Neury Mountains where the artifact lies, which are sacred to Worlders. Or so she thinks. Because once again, the military is playing its cards very close to its chest.

While scientists and soldiers have a hard enough time agreeing on anything, the civilians themselves fall out as the tale unfolds. Major Kaufman is forced to resort to ever more desperate measures in an impossible bid to reconcile his military duty of overseeing the understanding and potential use of the artifact, which may yet be a doomsday weapon, with the threat his mission poses to Worlders, championed by one of the few caring individuals in the novel, xeno-anthropologist Ann Sikorski.
Contact between our own race and Worlders has already had a lasting impact (and not all to her benefit) on Enli, the former outcast of 'Probability Moon', condemned to serve as a spy to atone for the crime of breaching the natives' "shared reality", which is both a genetic difference and a social code inaccessible to the visitors.

Nobody has to read 'Probability Moon' before taking on the complexities of this next taut-wired part of the trilogy. Kress spells out the essential in just a few pages.
But to miss out would be a pity. One of the strongest features of the first book was the depth and development of character. While this is by no means lacking here, especially regarding the new ones, the third strong strand in 'Probability Sun' is a gripping scientific conundrum.
When I reviewed its predecessor, I realised neither that the author's husband Charles Sheffield had been a trained physicist as well as a science fiction writer in his own right, nor that, sadly, he died last year. It's in this part of the series, dedicated to Dr Sheffield, that Nancy Kress challenges the reader to follow her and Capelo deep into the domain of quantum physics that gives the trilogy part of its name.
Herein lies one of the novel's several paradoxes. If there's one thing Tom Capelo finds it hard to stomach, it's a non-physicist laying claim to understanding what he's about or over-simplifying difficult concepts.
This is almost as bad in his eyes as the "soft science" he dismisses as "unmeasurable subjective feely-squirmy stuff" during one of his many rows with his fellows.
But just as the tetchy genius develops a grudging respect for Major Kaufman's attempt to come to grips with the science, Kress pulls off the achievement of taking concepts right out in the front of the field and flattering her readers that they've not only grasped some of the most intriguing ideas of our times, but also somehow understood where a Capelo might take them more than a century hence.