Alexander L. Pugh III (Jack) died February 7, 2025, in his mid nineties. Jack was raised in Philadelphia and Bala Cynwyd, PA. He attended the University of Pennsylvania, studying electrical engineering. His ROTC program led him to Hanscom Air Force Base in Middlesex Co., Massachusetts, a place where he settled. Jack's love of the nascent field of computer science led him to two Masters degrees in Electrical Engineering at MIT (SMEE, EE) where he collaborated with Professor Jay Forrester.

With Jay and others, he developed System Dynamics, a field of research and practice for understanding dynamic, emergent patterns in our social, ecological, business and political worlds. He and his wife, Julia, initiated and led the System Dynamics Society for almost 20 years. An entrepreneur in the 1960s, he developed the system dynamics software, "Dynamo," while co-founding with MIT Professor Edward Roberts the management consulting firm "Pugh-Roberts, Associates" (now Sage Analysis Group). There he worked until his retirement in 1995.

Jack met Julia (nee Spear), in the MIT Choral Society, and they married in 1962. Jack is predeceased by his parents, aunts, uncles, and brother, Walter Pugh (Darien, CT). He leaves behind his wife; children Rebecca, Katrina, and Alexander, and their partners Laurie, Peter, and Anneliese, grandchildren Isaiah (Jessica), Josiah, Sarah, Phoebe, and Benji.

Jack loved sailing, reading, fixing things, and hiking. After he retired, he was on the board of the Lincoln Public Library, the treasurer and webmaster of the First Parish Church of Lincoln and the captain of his sailboat, the "Mobjack," in which he won races over many years.

Memorial Services will be held on Saturday, May 10 at 2 pm in Duvall Chapel at Newbury Court, 80 Deaconess Road, Concord MA, and in July in Friendship, Maine.

In lieu of flowers, please send cards or consider a donation to the Midcoast Conservancy in Maine , P.O. Box 439 Edgecomb, ME, 04556.

Arrangements are entrusted to Dee Funeral Home & Cremation Service of Concord.