What is the climax of the novel and explain fully how the author arrived at this climax?
The highest point of the novel might arguably be Schindler's decision to help the Jews run the underground movement (Ch 17). But the true climax may not actually come until Chapter 37, when Arthur Schindler fully comprehends the meaning of the inscription on the ring given to him by the rescued workers. It reads: "He who saves a single life saves the world entire." (This is an echo of the Talmudic verse found in Chapter 2).
By Chapter 37, we, as readers (as well as Schindler himself) are able to comprehend the full meaning of this truism. No longer is it simply a worthy sentiment, but through Schindler's efforts, one man has made a measurable difference in the world.