The most interesting by far are John's gruellingly masochistic love letters to Rodin, for whom she modelled, and whose mistress she became. Sister of Augustus, and student of Henry Tonks and Whistler, Gwen John spent most of her life in Paris, where she made a sort of living as an artist's model, and as a painter of thin, mostly celibate women, nuns, schoolgirls and cats; paintings described by an anonymous critic as "limited and dim as reflections in a cup of tea". The biographer's thesis does not hold up, yet this is a meaty and worthwhile biography, unlikely to be bettered.