In December of 2000 Geoffrey Landis published his highly-anticipated first novel, Mars Crossing, to general acclaim. This is not another review of Mars Crossing; it has already received its fair share of praise. However, I may be able to shed some light on why so many hard SF fans waited so eagerly for a novel from Landis.

Shortly after the publication of Mars Crossing, Golden Gryphon Press brought out Impact Parameter and Other Quantum Realities, Landis's first collection, which covers sixteen years worth of short fiction. Most of the stories originally appeared in highly prestigious markets: Asimov's Science Fiction Magazine, Analog Science Fiction and Fact, the late, lamented Science Fiction Age, one of Patrick Neilsen Hayden's highly respected Starlight anthologies.

So many brilliant editors can't be wrong, and this is a solid collection: graced with a lovely cover by Bob Eggleton and a foreword by Joe Haldeman, it contains several award-winning and -nominated stories. One story ("A Walk in the Sun") won the Hugo, while others ("Elemental," "Ecopoiesis," and "The Singular Habits of Wasps") were nominated for the Hugo, the Nebula or both. Landis comes by his hard SF chops honestly; he's a Ph.D. physicist who works for NASA, and one of his experiments was on the Mars rover, Sojourner. The science in his stories is generally either gritty and accessible -- everyday stuff comparable to the physics underlying a case of whiplash after one is rear-ended -- or so far out it flirts with the fantastic.

As an example of the former, what could be more simple than a need to outrun the approach of night? This is the problem Landis gives his heroine, Trish Mulligan, in "A Walk in the Sun"; her space suit uses a solar-powered life-support system. Too long in darkness, and Trish dies. But Trish is stranded on the Lunar surface, alone -- and on foot.

And what could be wilder that piloting a diamond-hard dolphin body through the oceans of Uranus, as Leah Hamakawa does in "Into the Blue Abyss"? Cut off from her support team, at the bottom of a crushing gravity well, with only a fanatic for company, Leah's most pressing concern is whether the shallow energy gradient of the gas giant's ocean can power life.

But in both kinds of stories, the science is rigorously thought out and cogently presented.

Taking the hard SF aspects of his stories as (almost) a given, Landis manages to include enough variety to prevent the feeling of sameness that can bedevil a one-author collection. Landis's stories range from science fantasy ("Elemental," the oldest story in the collection) to action-adventure (the aforementioned "A Walk in the Sun," "Outsider's Chance"), to mind-bending exercises in extrapolation ("Approaching Perimelasma"), to a Sherlock Holmes pastiche ("The Singular Habits of Wasps"). Landis even includes a few that are essentially whimsies ("What We Really Do Here at NASA," which I'd tell you more about, but then I'd have to kill you).

But is a facility for hard SF, no matter how engagingly presented, enough to keep fans waiting for sixteen years?

I think not. I think Landis's fans have had sixteen years to become familiar with his ability to focus on the human side of science, scientists, and technologists of all stripes. I believe Landis's readers have had sixteen years to wonder if he could expand his stage and yet maintain his contact with the space inside the human heart.

Well, the wait is over. But before you rush out and read Mars Crossing, read -- or re-read -- the stories in this book.

Read the title story, "Impact Parameter," wherein a group of dedicated astronomers discover the world is about to end. Read "Ecopoiesis," in which the development of a Martian areology takes back seat to the blossoming of a singular, delicate love in a seemingly barren heart. Read "Snow," and "Dark Lady," two stories which, at first glance, seem to have little more in common with each other than damaged women protagonists, but which actually share a celebration of their ability to perceive the sublime in the underlying structures of the universe -- an ability which is no less human that the capacity for love or faith.

Perhaps that is Landis's greatest achievement -- not to take the science and make it gee-whiz, but to take the scientists and make them human. We see the teenaged girls of "Across the Darkness," who begin a journey into the unknown as little more than children, slaves to the dream of adults, and end it as adults in their own right who have taken that dream and made it their own; we see the imprisoned Russian scientists of "Beneath the Stars of Winter," who find a dignity in their pursuit of knowledge that can never be stripped away; we see the marooned pilot of "A Walk in the Sun," who knows what she must do to survive -- simple in concept, hellishly difficult in execution. And in them we see ourselves. We make do, we muddle along, though perhaps in not so dramatic a fashion. But we, too, must deal with the forces of Nature as we know them, and sometimes we still stop to wonder at the loveliness of a sunrise or full moon.

Landis's characters are real people who demand, and earn, our sympathy. Not only do we understand the science in Landis's stories, but through his characters we feel its importance. Like the creation of great art or the expression of extraordinary compassion, the pursuit of knowledge can define us as human because it gives us something beyond ourselves toward which we may reach. And what we discover is, in and of itself, beautiful.

Yet the pursuit of knowledge circles back on us, as well, as Landis shows through characters who are searching for their own pieces of the Ultimate -- an immutable, immovable Truth. How they perceive it and how they relate to it tells more about them than about their discoveries. Sarah, the homeless protagonist of "Snow," sees falling snow as "mapping a divergenceless vector field in three-dimensional space." It gives order to a shattered life. Jenny Hawke, of "Dark Lady," seems to live an orderly life as a respected physicist, but inside she is shattered -- as much by what she has learned and will never learn as by any cruelties suffered at the hands of others. "The stars," she says, "they are so beautiful from the gutter."

If there is a problem to be found in Landis's work, it is an occasional emphasis of science and character over story. For example, "Into the Blue Abyss" has a fascinating premise -- a manned expedition into the oceans of Uranus to search for life -- and a compelling protagonist in Leah Hamakawa, the female scientist with unspecified personal problems that have her on the run from Earth. In the end the story is a simple voyage of discovery; while Leah does grow more accepting of her problems they are not resolved, and the conflict Landis tries to introduce a scant three pages from the end of the story is too little, too late and would have been best left out. But this was a rare occurrence, and even in this case the premise was so fascinating I would have kept reading anyway.

So, back to the original question. Can Landis keep his rock-solid science and his compelling characters going for an entire novel?

After reading the stories in Impact Parameter I think I know the answer.

But I'll read Mars Crossing anyway.

Lori Ann White is a writer from the SF Bay area who has work forthcoming in Asimov's Science Fiction and Analog Science Fiction and Fact. Her uncle worked for NASA for many years and never told her what was really going on.