​D. Jeffrey (Jeff) Blumenthal

D. Jeffrey (Jeff) Blumenthal, 84, of Chicago, passed away suddenly on March 14, 2025. Born on June 12, 1940, in Evanston, IL, to Jeanne (Newberry) and Harold Blumenthal, He lived in Highland Park, IL until college. Jeff was a devoted husband of almost 59 years to Joan, nee, Hartstein, a loving father to Andy Blumenthal of Fayetteville, GA, and to Marianne Soto (Louis) of Libertyville IL. Papa to his grandchildren, Nate Blumenthal, Mia Soto, and AJ Soto. as well as many cherished nieces, nephews, and friends. He is preceded in death by his parents Harold and Jeanne Blumenthal, sister Shelia Spargo, and brother David Blumenthal.

Jeff attended Lake Forest Academy, in Lake Forest, IL where he was captain of the hockey team, on the track team, and played football. He loved the academic side of the Academy, especially mathematics and German. He was a dedicated alum, served on committees, and returned for Homecoming as often as he could.

In 1958 Jeff entered Cornell University, Ithaca, NY, majoring in Engineering Physics; his class was five-years, and 30 students. Years later it became a four-year program; he received a certificate of Advanced Engineering Study. Jeff was a member of Kappa Sigma fraternity. He active with the alumni association, reunions, and was a member of the Cornell Council.

Jeff decided to head west to Stanford University. In 1964 he earned a Masters Degree in Electrical Engineering and in 1969 an Engineer’s Degree (PhD with a practical thesis) in Engineering Economic Systems.

He met Joan in February of 1966. It was love at first sight; they were married 6 months later. His parents and Joan’s parents did not meet until the night of the rehearsal dinner.

While studying for his Engineer’s Degree, he worked as Sr. Research Engineer at Sylvania, GT&E in Mountain View, CA. It was during the Vietnam War and he had a top secret clearance. On the recommendation of his Stanford advisor he and Joan moved to Cambridge MA to work at Bolt, Baranek & Newman. Jeff was involved in a time sharing service and ARPANET project that later became the Internet.

In 1969, he decided to go out on his own; The Palo Alto Times wrote an article about him. Through that Jeff was asked to join a small consulting firm, On-Line Decisions/Planmetrics in Berkeley CA. This necessitated a move from Menlo Park, CA to Tiburon CA. The firm was growing and seven months later Jeff was asked to open a Chicago office. He was VP, Forecasting Division. Jeff was an expert witness for approximately 40 utility companies seeking rate increases.

In 1978, he formed the Jeffrey Corporation that specialized in business turn-around strategies, loan workouts, process engineering, activity/based costing, and startup business development.

Jeff joined Follett Corporation, a well-known leader in the educational services industry in 1985, first as a consultant and then as a full-time employee. He held several positions at Follett; Director of Strategy & Research; Corporate Director for Technology Development, Corporate Director, Strategic Planning & Information Systems, Director, Planning & Development; Co-Director, and Unified Software Project. He also authored a popular, widely distributed book on retail product marking standards in the college store. Jeff retired from Follett in 2007.

From 2007 to 2013, he worked for Blumenthal-Hart Ltd., Chicago IL, as Vice President. He assumed various roles.

In May 1970, Jeff and Joan welcomed their first child, Andy, and in June moved to Deerfield IL. Twenty months later, their daughter Marianne was born. He coached softball and was involved in his children’s activities when he was’t traveling.

An avid learner, Jeff had many hobbies, and interests. He truly enjoyed learning and was always seeking new information. He learned morse code and was an Expert Ham Radio (KB9CZ) operator until his death. Jeff loved to ride and fix bicycles. After retirement he was a volunteer at Working Bikes, a 501(c)3 in Chicago.

Jeff belonged to numerous civic and professional organizations. At age 32, he was the youngest trustee to be elected to the Deerfield Village Board. He also was a member of the Economic Club of Chicago, The Union League Club of Chicago, Treasurer of Union League Engineers’ Foundation,National Association for Business Economics, Co-founder of the NABE/CPS Economics After School Club, Chicago Principal for a Day, Member of the the Medill School Turnaround Project, MENtor in Real Men Read Project, Chairman of the Deerfield CATV Committee, Board of Directors and Treasurer of the Book Industry Study Group, Chairman of the Book Industry Systems Advisory Committee and the Columbia Yacht Club of Chicago.

In the late 70’s and early 80’s, Jeff was an Adjunct Professor at the J.L. Kellogg Graduate School of Management in the Managerial Economics & Decision Sciences Department. He authored his own textbook. In the mid 80’s, Jeff was an Adjunct Professor at Lake Forest Graduate School of Management where he taught courses on Strategic Planning & Quantitative Methods. From 2011-2013 he was an Adjunct Professor at Harold Washing College where he taught Statistics.

He rode a Kawasaki Vulcan Drifter for several years and belonged to the Chaiway Riders Motorcycle Club. Jeff loved the Lyric Opera of Chicago, and the Joffrey Ballet. He served on the board at the ParkShore Condominium Association, heading the Building Commission at a time when there was a major capital project that needed someone with his skills to push it off.

Jeff was avuncular, witty and loved a good pun. He will be dearly missed by all who knew him.

Services are private. A Celebration of Life will be held in May. In lieu of flowers, please send contributions to Lake Forest Academy, The Lyric Opera of Chicago or The Joffrey Ballet. Arrangements by Chicago Jewish Funerals - Skokie Chapel, 847.229.8822, www.cjfinfo.com