Edward McKnight Kauffer

In my journey of researching the 1920's I have come across the wonderful work of Edward McKnight Kauffer. He was an american artist who was most famous for his striking posters during the 20's, Which were mainly for the London underground. Although it has been said that the posters Kauffer designed were so intelligent and eye-catching that they would have equal rights if displayed at any reputable art gallery instead of on an Underground wall. What do you think?