The school bus honked and pulled over, startling Laura Schlitz as she was taking a walk in her residential neighborhood here. The bus driver leaned out and called to Ms. Schlitz: “Aren’t you the lady who won that big book award? I recognize you!” It is at such moments that Laura Amy Schlitz, whose book “Good Masters! Sweet Ladies! Voices from a Medieval Village” recently won the 2008 Newbery Medal, the most prestigious prize in children’s literature, realizes that she is not simply a school librarian anymore.