When Mary Horlock was a child, she'd only ever heard of one artist - her great grandfather Joseph Gray. What she didn't understand was why nobody else had heard of him.
Earlier this month, Elena and I met Mary at her home in north London to talk about her great grandfather; the WWI artist, the WWII camouflage artist and the man who's secret work for the War Office allowed him to live a double life.
Find out more about Mary's book here:
DoP / grading: Elena Lopez-Brea Sanchez
Director / editor: Mark Bowsher