The Boy in the Field - by Margot Livesey

In the waning days of the 20th century, siblings Zoe, Matthew, and Duncan discover a stabbing victim left to die in a field, and their lives each take on a new direction, and each finds a use for the library. Teenage Zoe begins dating an Oxford University student. She masquerades as an undergraduate and discussing things such as the Bodleian Library  keeps her from blowing her cover. Matthew, in an attempt to find the perpetrator of the crime, searches for clues in the local papers at the public library. Duncan becomes curious about his birth mother and decides he wants to find her. Zoe suggests he look her up in the phone books at the library. Additionally, other uses of the library are sprinkled throughout the work.