Read the book for the story of a man of twitchy nervousness, a chain smoker with a mania for soccer and a tenderness for his children, the ability to write lyrical music with bombs thundering all around him.
Read the book for the tale of a city of canals and bridges, palaces and concert halls, as it undergoes revolution, purges, and the longest siege in recorded history. All the horrors of the twentieth century are concentrated in a single city: St. Petersburg/Petrograd/Leningrad.
Read the book for the descriptions of the music. They will impel you to your local library to find recordings of the pieces he mentions, above all Shostakovich's Symphony No. 7, the Leningrad.