What is the author's tone in the nonfiction book, The Zookeeper’s Wife?

At the outset of the book, the tone is bright and hopeful. Antonina is living her ideal life with a husband and son that she loves surrounded by animals that fascinate her and a beautiful villa. The author uses rich descriptions to give the reader a clear picture of how wonderful life at the zoo must have been for Antonina before the war. She uses musical terms to describe the sounds of the animals and compares the zoo to Eden. When the war starts and the zoo and city are bombed, the tone of the novel turns dark. The author describes the animals’ sounds using words like “moaning” and “sobbing.” The destroyed buildings are described like wounded people. At the close of the book, the tone is hopeful when Antonina and Jan are reunited and the zoo is rebuilt.