Yves Klein was a French artist who is best known for his work in the field of monochrome painting. He first developed his signature style in the early 1950s, using a unique shade of blue that he had patented as "International Klein Blue." Klein believed that this colour was the essence of painting, and he sought to explore its expressive potential through a variety of different mediums. In addition to traditional painting and sculpture, he also worked with photography, performance art, and installation pieces. Though Klein's career was relatively short-lived - he died of a heart attack at the age of 34 - his work had a profound impact on the art world, and he is recognized as one of the leading figures of postwar abstract art.