## The GCHQ Puzzle Book

20 Oct 2016by GCHQ## The GCHQ Puzzle Book II

18 Oct 2018by GCHQ## The Ultimate Mathematical Challenge

1 Nov 2018by The UK Mathematics Trust- by Douglas Hofstadter
## Can You Solve My Problems?: A casebook of ingenious, perplexing and totally satisfying puzzles

6 Jul 2017by Alex Bellos- by Dr Gareth Moore
- by Robert Lomax
- by Ifan Hughes