Whitechapel Art Gallery, London, until 23 March
Hannah Hoch was one of the great revolutionary artistic innovators of the early 20th century. Along with Raoul Hausmann, George Grosz and John Heartfield she led the way in developing what has become known as photomontage or collage.
The avant-garde Berlin Dadaist group, of which Hoch was a member, was the most politically developed of the Dadaist groupings that sprang up across Europe and the US from around 1916. The Berlin Dadaists would use their new method of working not as a mere innovative technique in their "art practice" but, crucially, as a weapon.