The list author says: "I've been trying to track down a comprehensive list of novels in which the main character must follow clues in order to reach some goal. These kinds of books aren't quite mysteries (though they have mystery elements), aren't detective stories either (since the characters are normal people), and the term adventure is too broad. I thought I'd create a list myself since I don't think there's one out there.
The kinds of books I'm referring to involve the solving of a mystery, the locating of a person, the answering of some big question through the following of various clues. A protagonist may need to decipher anagrams, break out the metal detector, comb through an old diary, retrieve something from a safe deposit box--that kind of thing."
"Harriet spies on people and records everything in her notebook. People are the biggest mystery in Harriet's life, and after her notebook is stolen and read aloud by classmates, Harriet comes to understand much about friendship and relationships."