This book (and movie) is talking about leadership, decision making, conflicts of role, conflicts of policy. Ramsey (the captain) and Hunter (the executive officer) were all good soldiers, they both executed what they thought were correct. But different leadership style, different belief and grey area of policy made them confronted each other.
A good book (and movie), an interesting story that can make you think a lot. A lecturer of an university in Hong Kong even suggested his students to use this movie for leadership & organizational behavior analysis.