“In the olden times, in the old country of Latvia, a girl walks out of the city into the forest to gather mushrooms in a basket, like a child in a fairytale.” So begins Linda Grant’s absorbing ninth novel, The Story of the Forest. The year is 1913, the mushroom-gathering girl 14-year-old Mina Mendel, daughter of a prosperous Jewish flour merchant in Riga, who happens while walking to stumble upon a clandestine meeting of Bolshevik boys. They are singing. One of them asks her to dance. Exultant, a little afraid, Mina “felt something dislodge in her, the mechanism that was...