Bruce Lee's kung fu secrets are out and coveted again.

Bruce Lee's Fighting Method, a collective instruction book on Jeet Kune Do, or the martial art invented by the film star, was relaunched in China on July 20 - 40 years after his sudden death in Hong Kong.

The book features demonstrations of Lee's trademark movements by the man himself and a thorough instruction of Jeet Kune Do practices.

First published in 1988, the book, dubbed by many Jeet Kune Do practitioners as the bible of the martial art, has been reprinted more than a dozen times.

Although older editions have turned into hard-to-find cult classics and only a small group who know the art form remains, many say it's still important to commemorate the kung fu master.

"Lee's system is one of the most practical," Zhang Dawei, vice-secretary general of the Beijing Martial Arts Association, told China Daily. "Unlike those more performance-based and harder to rehearse types of kung fu, you can actually do Jeet Kune Do."

Lee's Jeet Kune Do is a combination of several different traditional martial arts styles techniques mixed with western boxing.

Hao Gang, the co-chair of China Jeet Kune Do International Federation said the art form not only shows Lee's unmatched fighting style but his spirituality as well.

"In his martial art style, lies the core of his spirit," Hao said. "Never flinch. It's not only a martial art — it's a life philosophy."

Lee grew up on the streets of Hong Kong and started practicing martial arts in the film industry at an early age.

Lee rose to stardom in Hong Kong and in the United States in the early 1970s. He was given a star on the Hollywood Walk of Fame and was named among Time magazine's 100 most influential people of the 20th century.

He died at 32 before the release of his hugely successful film Enter the Dragon.

"He's definitely a genius," said Zhong Haiming, who translated the instruction book in the early 1980s, at the book launch.

"He has left so many secrets for us to solve. Behind the martial art practices in this book, there is a philosophy."

Exercise in the way of Bruce Lee:

He ran 6.4 kilometers each day in 25 minutes.

He rode up to an hour each day on an exercise bike.

He skipped for half an hour to practice stamina.

He trained every day.

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