The Thirteenth Tale by Diane Setterfield

A little Bronte sisters, a little Victoria Holt, a little Daphne Du Maurier.....a lot Gothic tale of twisted family relations and two estates and gardens grand enough to mask the madness and hide the secrets. Very popular but very reclusive author Vida Winters hires Margaret, a shy antiquarian book dealer to write her life story. All previous attempts to learn about her life have resulted in biographies strange, mysterious and never believable. But none as strange and mysterious as the truth.