What is "Jeet Kune Do" Concepts?
Jeet Kune Do, was Bruce Lee's personal philosophy towards the Martial Arts. The most simplest explanation of JKD Concepts, would be "To embody your own expression of movement and discover it through the use of various martial arts".

As Bruce Lee himself was a scholar and philosopher, its important to note that Jeet Kune Do was very personal to him, and never intended to publicize it to the degree it is today. However his attitude changed over the course of his life, he came to believe that Jeet Kune Do was utterly vital to the development of all martial artists, with his JKD concepts, even being applicable to practices outside of martial arts.

Highlighting Bruce's philosophical insight,
the phrase "take what is useful, discard what is useless, and add what is specifically your own." depicts the idea that within martial arts, and art in general, the creative spirit, that inhabits all people, ultimately defines the very essence of human expression. Thus when studying the creative arts, one may discover the idea that art itself is an extension of oneself. The art and the artist is intrinsically one, and that exploration of different martial arts systems in "essence" would result in its full, and honest, expression.   

"No way as the way, no limitation as a limitation"