History and Theory of music can't be explained better
His long tenure as the music director of the New York Philharmonic is the foundation of his lasting fame for his conducting of concerts with most of the world's leading orchestras. Among his compositions: West Side Story, Peter Pan, Candide, Wonderful Town, On the Town, On the Waterfront, his Mass, and a range of other works, including three symphonies and many shorter chamber and solo works.
Bernstein was the first conductor to give a series of television lectures on classical music, starting in 1954 and continuing until his death. He was a skilled pianist, often conducting piano concertos from the keyboard. This is a short excerpt that shows that his understanding of music is extremely technical yet organic and holistic.