This unit from an as-yet uncompleted ESL, EFL, English language coursebook teaches English through the theme of mysteries. Students practice reading, writing, speaking, grammar and vocabulary.I find students love mysteries and solving puzzles. There's a reason for the international popularity of Law and Order, CSI, true crime shows, and even classic authors like Arthur Conan Doyle and Agatha Christie. They love to solve puzzles and riddles and have a lot to say about what they think.Activities a