Robert Middlekauff's early 1980s classic "The Glorious Cause" is often considered one of the best among academics, it also has a lot of interesting anecdotes that make it fun to read.

Which aspect of the war? Military history? Political? Particle battles? Biographies? Causes of the war?

I've been reading and studying the subject for years and I can't ever recommend a single book on the war, but if you have some questions about specific aspects of it I can definitely recommend some things.