Auction introduction: In London this June, Sotheby’s major Evening Sale of Modern and Contemporary art will include works by some of the most celebrated artists of the 20th and 21st centuries. Spanning the pioneering abstraction of Wassily Kandinsky through to the graffiti stencils of Banksy, this sale will encompass works of art that have pushed the conventional boundaries of visual art. The sale will be preceded earlier in the evening by a major auction of British Art.