Chapter 3 of Ellie Wiesel's autobiography Night holds the most figurative allusions to the night as a symbol of darkness, as well as of a sad inevitable transition to a new light; the reality of life within the concentration camp, and the reality of the horrors of the Holocaust.
With the words
Never shall I forget that night, the first night in camp, which has turned my life into one long night, seven times cursed and seven times sealed.
Here we see that Wiesel sums up his existence into that one night when the world, as he knew it, had been removed from underneath his feet. His entire life was about to change forever once the night ends and the light of a new, horrid day, begins.
Once that first night ends, Wiesel explains how the darkness transformed him; what he witnesses that first night in camp has traumatized him, made him mature by force, and has disenfranchised the Jews as a race. What was going to happen next? All that Ellie had was his memories of the past and his feeble hope for the future.
The night was gone. The morning star was shining in the sky. I too had become a completely different person. The student of the Talmud, the child that I was, had been consumed in the flames. There remained only a shape that looked like me. A dark flame had entered into my soul and devoured it.
Therefore, Wiesel uses the title Night to remind the reader of that one night which marked him forever. Wiesel also uses the salient traits of the night to explain the darkness into which his people were about to enter; the darkness that symbolizes death, desolation, isolation, and the end of all light.