I met an older man once when I was about 30 and just starting in electronics (i was still a restaurant cook) He saw me reading Walter Jung's OP Amp Çookbook and told me he had been part of a secret top secret International project to design the op amp ( using vacuum tubes) that occurred sometime between the end of WWI and the beginning of WWII . He said the project objective was to design a real-time analog computer fire control system for the big navy guns on battleships like the USS MISOURRI that could hit a moving target at 20 - 25 miles from a moving ship using an analog computer that had inputs from radar equipment.
He said the project was MORE secret than the Manhatten Project because they knew WWII was inevitable and WWI navy ships couldn't hit the broad side of a barn. Don't know if he was the "real deal" but he said the result of the project was the op amp .