The significance of this officer is that he served as naval aide to President Franklin Roosevelt throughout 1942, and subsequently as the first captain of the new battleship Iowa, in which capacity he carried his former boss to North Africa for conferences with Churchill and Stalin in late 1943. I'm gathering references for a model of the Iowa during this trip, including the privacy screens on the first superstructure deck and the two elevators that allowed FDR to go up to the bridge levels, so it's interesting to read about the actual journey.
The book provides a great insight into Roosevelt's wartime White House, but with a couple of bonuses. McCrea was charged with replicating Winston Churchill's map room in the White House, and selected a room on the ground floor next to the president's doctor's office. I'm partial to this room, and it was one of the ones I asked to see when Jamie and I had a private tour of the mansion some years ago. At that time its wartime use was commemorated by the map showing the Allied armies closing on Berlin on the day FDR died hanging over the mantel. That's long gone, I understand, but the history's still there.
He was also responsible for the creation of the presidential retreat Shangri-La in the nearby Maryland mountains, which would subsequently be renamed Camp David by President Eisenhower.
It is a very interesting story, and his stepdaughter did a good job of creating a narrative from the various sources available. I highly recommend it to the reader interested in this interesting corner of World War II history.