This is a summary of Erik Larson's New York Times best-seller Dead Wake: The Last Crossing of the Lusitania

On May 1, 1915, with WWI entering its 10th month, a luxury ocean liner as richly appointed as an English country house sailed out of New York, bound for Liverpool, carrying a record number of children and infants. The passengers were surprisingly at ease, even though Germany had declared the seas around Britain to be a war zone. For months, German U-boats had brought terror to the North Atlantic. But the Lusitania was one of the era's great transatlantic "Greyhounds" - the fastest liner then in service - and her captain, William Thomas Turner, placed tremendous faith in the gentlemanly strictures of warfare that for a century had kept civilian ships safe from attack. Germany, however, was determined to change the rules of the game, and Walther Schwieger, the captain of Unterseeboot-20, was happy to oblige.

Meanwhile, an ultra-secret British intelligence unit tracked Schwieger's U-boat, but told no one. As U-20 and the Lusitania made their way toward Liverpool, an array of forces both grand and achingly small - hubris, a chance fog, a closely guarded secret, and more - all converged to produce one of the great disasters of history. It is a story that many of us think we know but don't, and Erik Larson tells it thrillingly, switching between hunter and hunted while painting a larger portrait of America at the height of the Progressive Era. Full of glamour and suspense, Dead Wake brings to life a cast of evocative characters, from famed Boston bookseller Charles Lauriat to pioneering female architect Theodate Pope to President Woodrow Wilson, a man lost to grief, dreading the widening war but also captivated by the prospect of new love. Gripping and important, Dead Wake captures the sheer drama and emotional power of a disaster whose intimate details and true meaning have long been obscured by history.