The book is available as a single hardcover volume or a series of four paperback volumes. The text describes Bruce Lee's Kung Fu fighting techniques, philosophy and training methods. This book was originally written in by Bruce Lee. However, Lee decided not to publish this work as he feared that instructors would use the fighting knowledge in this text to promote themselves. In , after Bruce Lee's death, his widow Linda Lee Cadwell decided to make available the information on her husband's work.