Large scale world-building in science fiction is a balancing act. On the one hand, the world of the story—alien planet, space-based construct, far future polity—must exhibit a cohesion that feels real by the standards of, say, historical fiction. It must be a place the reader feels he or she could actually visit, a place with convincing physics and history, where the languages and iconography and geography convey a sense of inevitability. On the other hand, the characters must react believably to all this novelty, exist within the milieu in such a way as to bring the reader along on a fully immersive journey, and still present us with all the touchpoints of the human condition that make any fictive experience visceral and fulfilling.

Kay Kenyon does all this as a matter of course. With her new series, The Entire and the Rose, she demonstrates mastery of the techniques necessary to create plausible, memorable worlds through which her characters walk.

City Without End is the third book of a quartet following the actions of Titus Quinn, former starship pilot, and those whom he has drawn into orbit around him in his attempt to rescue his family from the world into which they have fallen, The Entire.

In many respects, The Entire is reminiscent of Narnia or Barsoom, a realm separated from our own universe by the thinnest yet most difficult-to-penetrate barriers. There is a touch of magic in Kenyon's creation. She gives us an inside-out universe, vast on the scale of our own reality, but bounded and contained, a bubble blown up by tremendous energies and filled with air and then populated by life forms. Each has its own place, separate and yet able to communicate and mingle by way of the River Nigh—a kind of space-time bypass that flows throughout The Entire. Huge, multifaceted, and complexly-realized, this is a land that offers near limitless possibilities of learning, adventure, and death.

Kenyon plays with superstring theory to construct this space, and gives us the Tarig, known to the denizens of The Entire as the Bright Lords, as architects and ultimate rulers. Tall, enigmatic, and autocratic, they live in mansions high above the land in a city known as the Ascendancy, and come down to mete justice, examine the interactions of the many cultures they have brought together, and to oversee their creation. They are as inscrutable and complex as the Entire itself, and Titus Quinn's enemies.

In the first book, Bright of the Sky, Kenyon relates the story of how Quinn, trying to escape with his wife and daughter from his crumbling starship, came to The Entire—snatched across the boundary by a young woman. She is apprenticed to a scholar who studies our universe—known to them as The Rose, because nothing like a rose can be found in The Entire—through the barrier between the two worlds. Quinn comes quickly to the attention of the Tarig and is made a "guest" of them—one in particular, the Lady Chiron. Quinn's wife and daughter are taken from him, and later, he is told they are dead. When he escapes back to The Rose, he is stripped of most of his memories. His employers, the Minerva Company, don't believe him—though they also hope he is telling the truth, because it would mean a new way to traverse vast stretches of space that may be safer and more reliable than their current method.

In the second book, A World Too Near, Quinn returns to The Entire bearing a weapon that will destroy the great machine the Tarig have built—the one that will convert The Rose, our universe, into a source of fuel to keep The Entire running. He learns that his wife and daughter live—the former lives in the labyrinthine keep where the machine has been built.

As the current book opens, Quinn has failed to deploy the weapon. He learned ultimately that it would destroy not only the machine but all of The Entire, and he has come to love this enigmatic, richly-peopled universe. There must, he decides, be another way to end the threat to The Rose and still preserve The Entire.

Through Quinn's journeys, he has begun to accumulate followers, various people of the assorted races who come to feel that he is a Great Personage—someone destined for important things. Of course, Quinn refuses to accept any of this. He wants his daughter back. He wants a normal life. He wants to save his family.

He can't have them.

His daughter has grown up in The Entire. She was a child when she arrived—memories of her parents are vague, and in truth she believes they abandoned her. She has risen to a position of command among the Inyx, a horse-like race of telepaths who require the close bonds of their riders, and soon becomes even more prominent in the course of a Tarig plan to capture her father.

Quinn's wife became a consort to one of the Tarig lords. In his own way, Lord Inweer honored her, but she lived in a beautiful prison. When Quinn returned, she helped him, costing her her life.

The young woman who first saved his life when his ship failed—Ji Anzi, a member of the most human-like of the peoples of The Entire, the Chalin—has bound herself to Quinn, and becomes his wife. She then must leave him at once in order to keep them both alive and the Tarig off-balance.

Kenyon's plots develop along intricate, satisfying lines, but what sets these books apart is her subtext—the morality of choice. Quinn has found his own fantasy world, in a way—his own Narnia, a place where he can act and make a difference. But in order for it to exist, he must take care that the "real" world from which he comes is both preserved and nourished. He comes time and again to realizations that he can't have them both—at some point, he will have to choose. He had to choose between rescuing his daughter and returning to The Rose to warn them of the danger from The Entire. He had to choose between destroying The Entire and yielding to the wishes of those he holds most important. He must choose between what he wants and what he must do. Kenyon very skillfully weaves this theme through the books in reifying skeins.

In fantasy, these worlds apart from our own stand as metaphors for dreams or for truth or for the imagination of childhood, and are fulcrums for coming-of-age tales, at the end of which the child gives way to the adult—one hopes with the wisdom the adventures were intended to impart.

But this is science fiction, and even though Kenyon's epic veers close to fantasy in some of its plot devices and cultural motifs, in the end The Entire is not a metaphor for Quinn's abandonment of childhood. It is a place he must come to terms with and probably make sacrifices for. It will not passively retreat to await the next child's discovery of it, waking with all its glorious subtext and rite-of-passage eloquence. In physics, it is a given that two objects may not occupy the same space simultaneously, and Kenyon has erected exactly that kind of situation, both as landscape and as desire. Quinn keeps moving closer toward the need to be Solomon and his delaying tactics will not suffice. He must, inevitably, decide.

Quinn is the man apart—wanting to belong, perhaps unable to by virtue of circumstance to be sure, but also because he is constitutionally incapable of the kind of surrender required. As such, he is a privileged observer, separate, aloof, and consequently responsible. He acts, and by acting, changes things—not necessarily for the better, and often to his regret.

Kenyon seems to be asking the question "What would you be willing to give up to have a universe where___?" Each of us can fill in the blank for ourselves, but the question doesn't change. What would you be willing to give up?

World building is a balancing act. It starts with a simple question: how much does reality cost?