Throughout history, great and terrible events have often hinged on sheer luck. Now, award-winning historian Andrew Roberts has assembled a team of his prominent colleagues, asking them to consider what might have happened if major world events had gone differently. Concentrating on their areas of expertise, distinguished historians re-imagine vital moments in history. George W. Bush’s former White House adviser, David Frum, considers a President Gore response to 9/11, while Conrad Black wonders how the U.S. might have entered World War II if the Japanese had not bombed Pearl Harbor. Whether it’s Stalin fleeing Moscow in 1941, as envisioned by Simon Sebag Montefiore, or Napoleon not being forced to retreat from it in 1812, as pictured by Adam Zamoyski, these essays posit a fascinating, sometimes horrifying parallel universe.