Final answer:
In 'The Fault in Our Stars', Augustus makes contact with author Peter Van Houten's assistant by email, discovering that Van Houten is living in Amsterdam and is willing to discuss his book's unsolved ending with them.
Step-by-step explanation:
In the novel The Fault in Our Stars, Augustus Waters makes contact with the reclusive author Peter Van Houten via email through his assistant, Lidewij. Augustus and Hazel Grace Lancaster, the novel's protagonists, find out that Van Houten is living in Amsterdam. They learn from the correspondence that he is willing to discuss the book and its unsolved ending with them should they ever find themselves in the city. This information fuels Hazel's desire to seek out the author and gain closure on the story that has deeply affected her.