A book about the tactics taught to armed forces

I was hoping to find a book that explains different tactics etc that are used by Marines, or SWAT and other tactically trained armed units/forces (Doesn't have to be from US. That's just because I'm thinking of what I've seen in the movies)

I guess I'm particularly interested in things like hand signals, detail on entering a room or 'clearing' a room etc.
I'm just always fascinated by it in the movies and would love to know the details.

Thanks very much in advance.