During Marx's long career - spanning over 70 years -she produced an impressive array of designs including stamps, seating fabric and posters for London Transport, books and book-jackets, wrapping paper, logos, rugs and menu cards. She also wrote and illustrated twelve children's books and co-authored - with her lifelong companion the eminent historian Margaret Lambert - two books about folk art, including the important 'English Popular Art'.

Her designs, usually abstract and geometric, were not only extremely fashionable, but also very practical. Towards the end of WWII she was invited to be a member of the Board of Trade Utility Furniture team, which designed large quantities of cheap furniture for people who had suffered bomb damage. Marx was responsible for creating textiles in as great a variety as possible from a very limited supply of yarns and range of colours, and in 1944 she was awarded the coveted title Royal Designer for Industry.

In 2006 the Gallery was presented with a complete set of Marx's prints from Matthew Eve and Eleanor Breuning. It is being shown together for the first time in a new exhibition in the De'Longhi Print Room from 10 January - 26 February 2012.