Where can I study military strategy without joining the Army and how useful is Sun Tzu these days?
Many schools offer military history and strategy as electives. There are countless books available to read if you don’t want to go to school, just try looking at your local bookstore. Sun Tzu’s Art of War is required reading in many (not all) advanced military training courses. Many aspects of his writing are just as useful today as they were when it was written. Try picking up the book and judging for yourself.