This book read like one of many earlier Sf books that I have read and enjoyed. We have a fantastic story and it builds up into an ending where all of humanity is at risk. Most of the characters in the story are more or less normal people trying to cope in a very different world. Of course you ask yourself sometimes why they did this or that but since they are normal people and not superheroes you have to expect some less than logical or sane actions.
It was impressive to see that you could write this story on only 300 pages. Many other writers would probably have used far more in order to expand a number of things to bring more detail into the story but the way Mr. Powell wrote it it worked very well. If you like classic Sf this is a book for you.
This book is a great start for Mr Powell. I hope he will continue with this line of writing and I will certainly continue to read him.