The Hercules II Course Lesson 4 ebook is for intermediate level lifters and continues from the previous Hercules Course 3 intermediate conditioning program. New exercises are given to add to the previous courses. 
The ebooklet also includes a comprehensive course on self defense, namely different Karate strikes. The conditioning of the hand as a weapon is explained. The pressure points of the body are explained with images detailing their locations. Several strikes with hands, elbows and feet are explained that allow one to defend themselves against attackers. The rare technique of the penny fist is also included, which is a brutal defense against an attack.
The exercises are all explained in detail and illustrated by Robert Nailon, an Australian golden era bodybuilder who was very good friends with Arnold Schwarzenegger.
Ebook is 27 pages long.