The "Ninja" series 1-5, featuring the beautiful full-color cover artwork of Gregory Manchess, published in the years between 1980 -1989, offers the higher-level philosophical aspects of the ninja arts with a look at the combat techniques in action. These were the original volumes that identified Stephen K. Hayes as an extraordinary writer-scholar willing to explore the spiritual significance of authentic warriorship to a depth unapproached by any martial arts writer before .

Vol. 1: "Spirit of the Shadow Warrior" deals with 5 elements of responding to threat, armed and unarmed combat, sensing the imperceptible intentions of others, special section on meditation for the warrior