1. What clues does Sleator provide the reader to indicate that someone will eventually be killed in the tower?

2. What is the basis for David's attraction to Angela? Why does Angela eventually break up with Carl?

3. In what ways is David actually different from Duplicate A and Duplicate B? Can the flaws in the duplicates be seen as extensions of David's own personality?

4. What complications arise from the creation of the first duplicate? What do David's actions, when faced with these problems, reveal about him and Duplicate A?

5. Trace how David's feelings toward Duplicate A change as you progress through the novel. What is the basis for these changes?

6. At the beginning of the novel, David sugests that he is rash and impulsive, making dates and appointments that conflict with others. Is there any evidence that this has changed at the end of the novel...