If I was asked this question, I would say Rex Applegate's "Kill or be Killed" provided they desired practical self defense. Next on the list would be W.E. Fairbairn's, "Get Tough" and lastly, Greg Anderson's "Weapons at Hand." They all go together very well, and provide excellent instruction for battle and street tested combat martial arts techniques, clearly written with excellent illustrations or photographs. What MA book or books would you recomend?