A glance at the copyright dates on the stories in this book shows that McAndrew has been with me for almost as long as I have been writing fiction. My own manuscript notes make that point even more clearly: the first piece of fiction that I ever published appeared in the April, 1977 issue of Galaxy magazine. The handwritten date on the first page of the manuscript of “Killing Vector,” my first McAndrew story, is just two months later: June 15, 1977. Since then, at apparently random intervals ranging from a few weeks to a few years, I have produced another tale of Arthur Morton McAndrew and his long-time and long-suffering companion, Jeanie Roker.

What’s the fascination of these characters for me, and why do I return to them again and again? As a related question, is there any pattern to the stories?

First, let me point out that the order in which they appear in this volume is not the order in which the stories were written. Chronologically, the order would be “Killing Vector,” “Moment of Inertia,” “All the Colors of the Vacuum,” “The Manna Hunt,” “Rogueworld,” “Shadow World,” “The Invariants of Nature,” “Out of Focus,” and “The Fifth Commandment.”

The most obvious point about these stories is that each revolves around some central issue of science. I go into that subject in detail in the Appendix at the end of the book. Whenever I become interested in something, especially when that something involves physics and astronomy, a McAndrew story is likely to emerge from my hindbrain.

That explains the chosen themes, but not McAndrew himself. I might suggest that he is some form of alter ego, the me that I wish I were, except that others have already assigned that role to Behrooz Wolf (of Sight of Proteus, Proteus Unbound, and Proteus in the Underworld).