Leonard Bernstein (25. August 1918 – 14. October 1990) was an American composer, conductor, and pianist noted for his accomplishments in both classical and popular music.

Bernstein was an eclectic composer whose music fused elements of Jazz, Jewish music, theatre music and the work of earlier composers like Aaron Copland, Igor Stravinsky, and George Gershwin. Some of his works, especially his score for West Side Story, helped bridge the gap between classical and popular music. 
Bernstein was one of the major figures in orchestral conducting in the second half of the 20th century. He was held in high regard amongst many musicians, including the members of the Vienna Philharmonic Orchestra, the London Symphony Orchestra, and the Israel Philharmonic Orchestra. He was probably the main conductor from the 1960s onwards who acquired a sort of superstar status similar to that of Herbert von Karajan.

From 25. August 2017, Bernstein’s 99th birthday, and continuing through his 100th year until 25. August 2019, Bernstein at 100 celebrates Leonard Bernstein’s 100th birthday worldwide.