When the Winchester Mystery House celebrated its 100th anniversary two years ago, Robin Chapman was one of several historians asked to speak to mark the centennial. Intrigued by what Sarah Winchester had done with the acreage surrounding the mansion, Chapman embarked on a research project. She will share her findings in A Winchester Mystery in the Valley of Heart's Delight, on Wednesday, Oct. 15, 5:30-7 p.m., at the Los Altos History Museum