IN THIS SERIES, I continue to owe thanks to those who good-heartedly agree to read drafts and advise me on science and technology. Deep gratitude to my husband and first reader, Thomas Overcast; science fiction writer Karen Fishler; writer of hard physics science fiction Robert Metzger; theoretical physicist Todd Brun; and, for advice on traumatic injuries, my EMT son, Matt Balser—all of whom were kind enough to read and comment on various parts of this book. Departures from the strictly possible and fictionally plausible are on my own shoulders. To my agent, Donald Maass, my sincere thanks for setting me on the path to this story. I am indebted to my editor, Lou Anders, for his suggestions and contagious passion for this series as well as for conceiving the perfect matchup of my story with the artwork of the superb Stephan Martiniere.