During the interwar years, Betty Joel (1894-1985, née Mary Stewart Lockhart) was an enormously important figure in the world of furniture, textiles and interior design. Yet there is every chance you have never heard of her. In 1921, and without any formal training, she set up a company with her husband, David Joel, and began designing and producing furniture which not only the encapsulated the period's modernist style and elegance, but was also well-made, practical and thoughtfully designed. (This is the London showroom at 25 Knightsbridge.)