As usual Landau Fine Art is showing work by acclaimed and historic artists. This site is supposed to be about getting people who love art but haven't really followed it in detail information. The assumption that people know who all these artists are would be an easy one to make; it might also be erroneous. It is no shame to NOT know them--but you should if you are interested in art.
For Kandinsky, often considered the first abstract artist, you might want to look at the Guggeheim website or MoMa (New York).
Ernst's work seems beautiful and dreamlike today but that is with the prism of time. When he was working? His paintings were still dreamlike and beautiful but they were also shocking in their abrogation of artistic orthodoxy; he was not interested in what artists were "supposed" to create. He fought in World War I and emerged from that experience critical of Western culture. As noted elsewhere he was profoundly interested in works by the mentally ill and children. Find out more about him at the Tate Gallery (London).
Klee, a Swiss/German artist, is certainly one o the most important artists of the 20th Century. His work is the meeting place for many of the "isms" of the era: surrealism, expressionism and perhaps most importantly, cubism (among a few others). Klee was friends with Kandinsky and the two were members of "The Blue Four (Lyonel Feinenger was also one of the four). He was also a musician. His work was reviled by the Nazis and his family moved to Switzerland in the early 1930s. He died there in 1940 from scleroderma. Find out more about him at the Metropolitan Museum website.
Dubuffet's work was shown by numerous galleries during Art Week 2014. His work is idealistic and his philosophy embraced what is, today, referred to as "outsider art." Find out more about Dubuffet at the Fondation Dubuffet website.
Gris (aka Jose Victoriano Gonzalez-Perez) was a Spanish cubist painter who spent most of his career in France. You can see his complete works HERE.