I've never gotten around to finishing this book before, even though I've enjoyed a lot of van Vogt's writing. The last time I tried to read it was about ten years ago and I ended up losing my copy of the paperback. The book is a compilation/re-write of five short stories. I had read the comic book version of the first, "Black Destroyer" before. I had also heard that this book was the "inspiration" for the movies It! The Terror from Beyond Space and Alien, but while some scenes in both can be said to be drawn from van Vogt's book, it isn't a proper correlation. This book does seem to be one of the inspirations for Scientology, since I know van Vogt and L. Ron Hubbard were colleagues and the mind-controlling science of Nexialism is rather disturbing close in its applications to "rumors" of what the cult is, minus all that evil Thetan malarkey. The individual stories are interesting, but the work as a whole just doesn't really come together as a flowing story. This is more like four or five episodes of Star Trek strung together at once. Not bad, not good, but interesting. It could've been a lot better.