>> Does anyone know how to reach Thomas Lindgren, who wrote the 1990 book "Glory and Failure" about Babbage and others who built difference engines?

Disregard. I was informed it's Michael, not Thomas, and someone pointed me to his website.

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NJIT logoEvan A Koblentz
Staff Writer
Office of Strategic Communications
evank@njit.edu
(973) 596-3065
https://web.njit.edu/~evank/
@TechnicallyEvan