Pearl Harbor by Craig Nelson. This is one of those books that I will re-read in the future. Not because it is hard, but because it offers several layers of understanding the history of WW2. The horrendous descriptions of the war and scale of the destruction is quite shocking. The author can take you to the mind of the characters to try to understand all the decisions they had to make at difficult times.
The first half of the book is very well researched. It provides all the primary sources of information and the author does his best to maintain a neutral tone, although he also mentions that it was hard to get materials from some sources in Japan. Probably my favorite part is the last chapter, because of the analysis of the consequences of the attack, such as the creation of the CIA and other organizations.