“The Warriors” wasn't just the first tale of the kzinti. It was the first story I ever offered for sale. I was daydreaming in math class, as usual, and I realized that I'd shaped a complete story. So I wrote it down, and bought some magazines to get the editorial addresses, and started it circulating.

It was years before anyone bought it. By then I'd rewritten it countless times, trying out what I was learning from my correspondence writing course. Fred Pohl (editor of Galaxy and Worlds of If in those days) saw it often enough that he eventually wrote, “I think this can be improved… but maybe you're tired of reworking it, so I'll buy it as is.” It was probably his title, too.

The kzinti look a little blurred here, don't they? I mean, if you've known them elsewhere. Subsequently they changed in several ways.

I learned to answer John W. Campbell's challenge: “Show me something that thinks as well as a man, or better, but not like a man.” The kzinti took on more detail, gained greater consistency and lost some of their resemblance to humanity. They were born as one of a thousand catlike aliens in science fiction. As I learned how to make an alien from basic principles, body and mind and soul, the kzinti became more themselves.

At the same time they were changing in another way, evolving over several centuries. The Man-Kzin Wars changed them far more than they changed mankind, because the wars killed off the least intelligent and most aggressive.

This book was conceived in a casual encounter.

Marilyn and I were driving to a Nebula Awards banquet with Jim Baen in the back seat. She drove, we talked…

I knew about franchise universes. Jim and I had edited The Magic May Return and More Magic, tales set in the Magic Goes Away universe but written by friends whom we had invited in. I had played in neighbors' playgrounds, too. “A Snowflake Falls” used Saberhagen's “Berserkers,” by invitation. I'd written a tale set at Lord Dunsany's “edge of the world,” and a report on the year the Necronomicon hit the college campuses in paperback, and a study of Superman's fertility problems.