Find a Stranger, Say Good-Bye — Lois Lowry

Natalie Armstrong has everything: she's smart and beautiful, has the perfect boyfriend, early acceptance to college, and a loving family. But the summer she turns seventeen, she finally decides to ask some unanswered questions: Who are her biological parents and why did they give her up when she was born?

These questions take her on a journey from the deep woods of Maine to the streets of New York City, from the pages of old phone books and a tattered yearbook photo to the realization that she might actually meet her biological mother face-to-face.