'A writer for children must be happy without fail...'
In the time of Stalin, when words could kill, one man, Kornei Chukovsky, waged a war for the minds and dreams of children using only his imagination and love of the fantastic.
For millions, his tale of a tyrannical cockroach became a metaphor for Stalin's reign of fear.
For others he simply brought joy at a time when none was on offer.
Today he is still as loved as ever, but newly published diaries reveal the true nature of his struggle with the Soviet system.
Michael Rosen explores his life and legacy.