In my early years I was utterly devoted to Ace Doubles, which bound two short novels back-to-back — you’d read one, then flip it over and read the other. The great SF editor Terry Carr once said that Ace would publish the Bible as a Double: War God of Israel and The Thing with Three Souls.
![](https://cdn.uploads.micro.blog/404/2023/rocannonkarchee.jpg)