Night can be interpreted as delivering many types of lessons.
Obviously, the book is a record of an example of man's inhumanity toward other men. The deprivations and torture heaped upon the Jewish prisoners in the concentration camps is horrific beyond description. As a history lesson, the book should be a lesson to every human being about the potential for cruelty within the human spirit, the dangers of unquestioningly following one leader's plan, the need for all to be informed and ready to take a stand against acts that contradict the common decency.
On another level, Night is a testament to the incredible strength of the human spirit. The dedication of Elie's father and others to the traditions of their faith under the worst of conditions, the determination to do whatever was necessary in order to survive in spite of incredible hardships, the instinct that repeatedly caused prisoners to care for each other - there are lessons of tremendous inspiration in the story.