While eminently readable, The Longest Year: America at War and at Home in 1944 has some egregious mistakes. Example: "Meanwhile, British aircraft designers had produced a powerful new engine, the Merlin, which would not fit in their array of airframes." p.53
Over 30 types of warplane produced in Britain, including the central workhorses - the Hurricane, Spitfire, Lancaster, and Mosquito, were powered by one or more of the 112,000 Merlin engines built in the UK. Together with 55,000 Merlins license-built by Packard in the US, it was the second most-produced aero engine in World War 2, world-wide.
Another example: The naval Battle of the Phillipine Sea in June 1944 was one of the largest in history. The Japanese ships were always to the west of the US fleet. The chapter repeatedly reverses the locations.