Dive, dive

Any account from Robert Ballard, the discoverer of the Titantic, is bound to be a tale and a half. In Exploring the Lusitania (Weidenfeld & Nicolson, £20, ISBN 0 297 81314 5), the underwater sleuth tries to unravel the mystery of the liner that was sunk by a German torpedo in May 1915. Why did the boat sink so quickly? Was it carrying munitions? And was its demise sanctioned by the British to draw the United States into the First World War?