I've always had a secret fondness for Ace Doubles--what could be better than two science fiction books in one? My mother's shelves used to be full of them when I was a kid, so when I started finding them in bookstores as an adult I decided to build a collection of my own. Most are lesser-known works by well-known authors, or works by lesser-known authors, and for all the issues that I have with classic science fiction (mostly due to technical advances being projected while social advances were left far behind), its strength is in the unrestricted creativity that authors showed.Not all books are created equal, of course, and my overall rating reflects both books (novellas, really, when taken individually) but each deserves its own rating.Alpha Yes, Terra No! * * *While this book had its moments of stunning prescience (I read paragraphs that could have precisely described the world today), it didn't hold my attention particularly well and tended towards the preachy.The Ballad of Beta-2 * * * *This one clipped along at a much faster pace, and I was pleasantly surprised by how it didn't fall into the pitfall of overt sexism that I see over and over again. While I liked the story in and of itself, there were also details of the setting that I would love to see spun off in other directions as well.