***Test your code-cracking abilities with 300 of the Telegraph''s most addictive puzzles.How does it work? Well, each grid contains numbers that correspond to a letter of the alphabet. With the help of a few solutions to start off, all you''ll need to do is complete the puzzle by working out every letter''s respective number. The perfect mental workout and screen-free activity, The Telegraph Big Book of Codewords 1 will provide hours of entertainment, whether you''re at home with a cup of tea or passing the time on a long commute.