Heda Kovaly
The author and essayist who uses this book as an opportunity to spread awareness about the horrors of the Holocaust. The Kovaly family was abducted from their home in Prague and sent to a ghetto for some time until Auschwitz was began, and then they were shipped to that death camp. Heda survived the camp and was liberated at the close of WWII, but when she married a Communist, he was executed in the political aftermath, leaving her alone with an infant son, Ivan.
Rudolf Margolius
Heda marries a man named Rudolf who is drawn toward the ideas of Marxism and Communism, but since the Nazi party was Socialist, and since historically, anti-Communists are paranoid about competing political movements, he ends up being assassinated, killed for his political opinion. That leaves his wife, Heda, a literal Holocaust survivor, without resources.
Ivan
Ivan is Heda's child with Rudolf who ends up being raised by her alone for some time until she remarries, but it's clear that she is more excited about the future of Prague and the new cultural movement blossoming there, so Ivan's childhood is quite a wild ride, because Heda's own life was uprooted several times when she was a single mother to him after Rudolf's untimely execution.