I really enjoyed this book. I'm a couple of decades over the target age for this one but it was a great quick read and something a bit different for me. My ten year old has also started it and he is enjoying it so far. There are some great characters especially some really strong female characters. I love Robyn especially as she seems so tough but is a bit naive too at times and gets herself into a lot of trouble. For older children this is a good introduction to WW2 as there's a lot of the reality of wartime without too much of the horror of it. I did find the ending a bit rushed as it all built up to solving the mystery and then suddenly skipped a few months it felt like an exciting bit was missing , which was s shame. I did enjoy reading a bit about the history of Bletchley park at the end and the author's own connection. I would definitely read more in this genre.