The last surrealist and the first abstract expressionist. This has been said of Arshile Gorky. So have a lot of other things about his interesting yet tragically short life. Found dead in 1948, hung by his own hands, Arshile Gorky was an unorthodox painter and the father of ab ex (abstract expressionism).
To give you an idea of his influence:
Mark Rothko was a student of Gorky’s at the New School of Design in Boston.
Willem de Kooning was a close friend and considered him a mentor.
André Breton—the self-styled pope of surrealism—was a big supporter of Gorky’s.
Among the artists he influenced were Cy Twombly and Helen Frankenthaler.
Gorky’s art became most like Gorky’s art in the 1940s. Before then he had been heavily influenced by Picasso, Cézanne, and Joan Miró, amongst others. An example below:
So to get the best idea of Gorky at the height of his artistic prowess, the remaining examples are going to be paintings finished after 1940. Formal elements of note are the use of biomorphic forms, the importance/adept use of line, and the lyrical use of colour (although there were fewer and less bold colours in the later years).