(CNN) Bruce Lee, the martial arts icon, was being interviewed by a Hong Kong talk show host when the man asked Lee if he saw himself as Chinese or an American.

"Neither," Lee said. "I think of myself as a human being."

Forty-three years after his sudden death in July of 1973, more people are starting to think of Lee as something else: A profound thinker whose mind was as supple as his body.

That may seem like an odd claim. Lee was a fighter, not a philosopher, according to popular perception. He left behind some of the most exhilarating fight scenes ever captured on film in movies such as "Enter the Dragon" and "The "Chinese Connection."

But his legacy also includes a revolutionary book on the martial arts and Eastern philosophy, and seven volumes of writings on everything from Taoism, quantum physics, psychotherapy and the power of positive thinking.

John Little, who examined Lee's papers after the actor's death, says he was stunned when he first entered Lee's library. He had at least 1,700 heavily annotated books. That's when he realized that Lee sharpened his mind as much as his body.

"The philosophy of Lee is more powerful than the martial arts of Lee," says Little, author of "The Warrior Within: The Philosophies of Bruce Lee." "Everything that Bruce Lee did flowed from his mind and his thinking."

And it flowed from his pride in his Chinese heritage as well.

English-born philosopher Alan W. Watts was such a favorite of Bruce Lee that he required his martial arts students to listen to Watts' lectures.

Lee was a devotee of Alan Watts, a 20th century British philosopher who introduced Eastern thought to Western audiences. Lee would tape Watts' lectures and play them back to his martial arts students in class.

Lee, too, saw himself as bridge between the East and the West. He wanted to show Americans the beauty of Chinese philosophy and its culture, his friends and biographers say.

"He told me that he could educate people about the East more in films than in books," says Dan Inosanto, one of Lee's closest friends and his training partner. Inosanto filmed an insanely exciting fight scene with Lee in "Game of Death" where both battled one another using Lee's signature weapon, nunchakus, a weapon that consists of two sticks connected by a short chain.

Muscles like warm marble

Of course, those old enough to remember when Lee was alive didn't go to his films to learn about esoteric Eastern teachings. They wanted to see him kick butt.

And Lee obliged. He hit the American movie screens in the early 1970s like a tsunami.

The philosophy of Lee is more powerful than the martial arts of Lee. Everything that Bruce Lee did flowed from his mind and his thinking. John Little, author of "The Warrior Within: The Philisophies of Bruce Lee."

American audiences had never seen an action star like him before. The liquid grace of his movements; his feline quickness; the weird, high-pitched shrieks he gave off during combat. People squealed in delight so much during his films that a viewer rarely heard all the dialogue.

Lee was a racial pioneer, too. Here was an Asian man who wasn't depicted as a bucktoothed buffoon or fortune-cookie-quoting sage. He was an unabashed sex symbol. Women marveled over his lithe physique; one person said touching his hardened muscles was like touching "warm marble."

But Lee's mind -- his grasp of philosophy and his willpower -- was the engine that powered his physical prowess, says Bruce Thomas, author of "Bruce Lee: Fighting Words."

"What Lee did was harness energies outside the ordinary energies that are used for daily life," Thomas says. "The martial arts were a way a life for him, a genuine path, a means of psychological development and spiritual development."

Lee's 'go-to' philosopher

Another thinker who helped Lee harness those energies was Jiddu Krishnamurti, a philosopher born in India who taught that truth can't be found through any religious tradition or dogma.

"In oneself lies the world and if you know how to look and learn, the door is there and the key is in your hand," he wrote. Krishnamurti's emphasis on self-reliance and disdain for mindlessly following tradition shaped Lee's approach to the martial arts.

When Lee was alive, the martial arts world was rigidly divided by different fighting styles. He borrowed from virtually all of them to create his own revolutionary fighting called "Jeet Kune Do," which he later turned into a book.

Today, Lee is often called the father of MMA, or mixed martial arts, for his willingness to be, as he once said, "not one style, but all styles."

"Krishnamurti was his go-to thinker," Thomas says. "He taught that one must come to the present moment and not be tainted by rituals and dogmas. He took everything Krishnamurti said about religion and applied it to the martial arts."

How Lee's mind helped him survive a crisis

Lee's devotion to philosophy could have just remained an abstract pursuit. But it was also key to his physical speed and power. One martial artist said that Lee had the ability to move from perfect stillness and "explode like a firecracker."

Lee could do that because he was able to tap into what ancient Chinese philosophers called "chi."

In his book, "The Warrior Within," Little described chi as a "vast reservoir of free-flowing energy" within all people that "when channeled to our muscles, can give us great strength and, when channeled to our brain, can give us great insight and understanding."

Lee's ability to summon chi at will was the culmination of years of philosophical contemplation and physical training, his biographers and students say.

Lee once described what it felt like to summon these energies within himself:

"I feel I have this great creative and spiritual force within me that is greater than faith, greater than ambition, greater than confidence... Whether it is the Godhead or not, I feel this great force, this untapped power, this dynamic something within me."

Lee also unleashed those energies through positive thinking. He was a fan of Norman Vincent Peale and read books such "As a Man Thinketh," by James Allen. He would also jot down homespun aphorisms in his spare time like, "Pessimism blunts the tools you need to succeed."

Lee's philosophical beliefs could have been confined to books, but they were refined by events in his life that would have broken lesser people.

First, he had to deal with racism -- from both sides.

He was born in San Francisco, but grew up in Hong Kong in an affluent family. His father was an opera star and Lee became a childhood actor who appeared in at least 20 Chinese films. Lee started studying martial arts when he was 13 but his instructor stopped personally teaching him when he learned that Lee's mother was part White, biographers say.

I feel I have this great creative and spiritual force within me that is greater than faith, greater than ambition, greater than confidence. Bruce Lee, martial artist and philsopher

That experience shaped in part his decision to teach the martial arts to Westerners after he moved to America when he turned 18, some say. Teaching the martial arts to Westerners was taboo at the time, but Lee didn't care, says Doug Palmer, who was one of Lee's first students in America.

"I think the fact that he [Lee] was part white had something to do with it," Palmer says about Lee's decision to teach Westerners. "He himself had to overcome obstacles in Hong Kong because he was part white."

Lee then encountered racism from Hollywood.

He had gone to Hollywood with an idea for a television drama about the martial arts. They took his idea but rejected him for a role in the series because they thought he looked too Chinese for an America audience. They gave his role to an American actor and dancer. The drama would eventually become a hit television show called "Kung Fu."

Lee also suffered a crippling back injury during training. Doctors told him he would never walk properly again and could never practice the martial arts. It was a low moment in his life. He was bedridden with a wife and two young children to support. At one point he only had $50 in the bank. He could have fallen into a debilitating depression but he overcame his injury through positive visualization, and he used that time to write his groundbreaking book, "Jeet Kune Do," says Thomas, one of his biographers.

"He healed himself," Thomas says.

Lee's belief in the power of positive thinking comes through in a letter he wrote to a friend during that shaky period in his life.

He wrote:

"I mean who has the most insecure job than I have? What do I live on? My faith in my ability that I'll make it. Sure my back injury screwed me up good for a year but with every adversity comes a blessing... Look at a rain storm; after its departure everything grows.

Lee's legacy today

Lee eventually broke through. He went to Hong Kong to make a series of films that caught Hollywood's attention. He then returned to Hollywood to make "Enter the Dragon," which became a huge hit.

But Lee never lived long enough to see the culmination of all of his work.

Just days before the American release of "Enter the Dragon," in 1973, Lee died in Hong Kong from an allergic reaction to pain medication he had taken. He was 32. Lee's son, Brandon, who would follow him into the martial arts and film, would later die in 1993 from a freak accident with a prop gun on a movie set.

Lee's friends still miss him. They talk less about his fighting ability and more about what fun he was to be around: his restless questioning, his optimism, his goofy sense of humor and his loyalty to friends.

"He was a very charismatic person," says Palmer, who is now an attorney in Seattle. "He could dominate most situations. You walk into a room and in most cases he would dominating the conversation."

Lee's influence transcends the martial arts, Inosanto says.

"I got letters after he died from people from almost all walks of life, from musicians to skateboarders -- they all said he influenced him," Inosanto says.

Lee's global popularity is matched by only one other person, Inosanto says.

"Muhammad Ali and Bruce Lee are the most recognizable faces in the world," Inosanto says. "I was very lucky to have stumbled onto him. I never had a dull moment with him."

Lee's family is introducing the martial artist to a new generation today.

Lee's widow, Linda Lee Cadwell, and his daughter, Shannon Lee, established the Bruce Lee Foundation "to share the art and philosophy" of Lee. It gives out scholarships to students who embody Lee's passion for learning and provides martial arts training to underprivileged youth.

Lee's legacy is expanding in other ways too. There are now more authors writing not so much about Lee's fighting ability but his resilience as an example to anyone who wants to express their individuality and overcome obstacles in life.

At the foot of Lee's grave site in Seattle is a stone tablet with an inscription that reads: "Your inspiration continues to guide us toward personal liberation."

Lee's legacy is now bigger than any punch he ever threw.