Teacher, scientist, rock climber and lifelong explorer, Sam Tatnall passed away on June 16th with his wife Bitsy and goddaughter Daisy at his side. He is survived by his stepson, Marshall Field, brothers Frank G. Tatnall and David V. Tatnall and sister, Caroline Jopes. Trained at Cornell, Haverford College and Harvard, he taught AP physics and computer science to boys for 22 years at Chestnut Hill Academy, William Penn Charter School and The Haverford School in Philadelphia. He co-founded software development firm, Scherrer Resources and then joined Mobius, developing desktop and web applications. A devotee of the natural world, he was an avid organic gardener at home in Bedford, NY and rock climbed around the world. His mentorship of students and coworkers, generosity of spirit and integrity of character will be remembered dearly. There will be a celebration of Sam’s life at the Harvard Club in the fall. Contributions in Sam’s name can be made to music or environmental organizations.