The only thing that limits our knowledge is ourselves, "less constrained than in a library" implies that a library is a limitless opportunity for knowledge. You could pick up any book and learn something from it. In this way, the library has more opportunity for learning and creativity than somewhere compared to, say a forest, where you're limited to the knowledge you gain from experiences or prior knowledge.
How does Wiesel's father avoid being "selected" at Gleiwitz and why does Wiesel run after him to the left? When his father was selected Eliezer is able to inch his way through the lines and bring him back to the "right" area where the people that were not selected were waiting.
