A close-up shot of the cuneiform script on an ancient column (below)The Trustees of the British Museum The Mesopotamian Riddle Joshua Hammer (Simon & Schuster) What does it take to decipher an extinct writing system? If Joshua Hammer’s new book The Mesopotamian Riddle: An archaeologist, a soldier, a clergyman, and the race to decipher the world’s oldest writing is anything to go by, the main requirements are some ethically dubious archaeological digs and a lot of rampaging testosterone. The book is Hammer’s account of the deciphering of cuneiform, the oldest known writing system. Cuneiform was invented in around 3400 BC in Mesopotamia. It was used for…