I'm guessing that those who haven't read this book, haven't read Nevil Shute before. This book is typical of Shute's middle period, in other words, just about as good as he gets. Shute wasn't a great writer, in the sense that he didn't write any classical works of great literature like, say, Arnold Bennett or Dickens. But, Shute was certainly a very good writer; virtually all his books are insightful, interesting, entertaining, and easy to read. By which, I do not mean they are kids books; just technically very good English from the point of view of readability. Shute's books are also exciting in an easy-paced manner, he was a master at building and holding tension in a way that the reader barely notices until, all of a sudden, you realise you can't put the thing down. This makes his books very easy to re-read, again and again.
The Pied Piper follows the trail of 70-year old John Howard, a retired British solicitor on holiday, through France at the outbreak of WW II. The description of the effect of their lightning defeat on the French is masterful. But the essence of the plot is Howard's attempts to get back to Britain, through increasing mayhem and failure of all the systems we take for granted, accumulating a varied collection of children on the way. There is violence in this book, obviously the setting demands it, but it is never gratuitous. Rather, the violence makes the narrative believable, enhances understanding of existing characters, and introduces new ones. Children in novels are rarely believable, largely because they are incidental to the plot and the author has forgotten childhood. Neither of these things applies to this book; not only does Shute understand children, but he knows how to make them important in themselves, characters demanding and deserving respect - a rare skill. As I write this, I've just promoted this book from 4 to 5 stars. I've never done that before!