If one counts Clive Cussler (or, in this case, “Clive Cussler’s”) novels as technothrillers, then one called Fire Ice was the first techno-thriller I read. Then it gets weird because well, I honestly can’t remember the next ones I read until reading the The Big One alternate history novels, which is kind of like getting into cinema by watching The Room, Who Killed Captain Alex, and Plan 9 from Outer Space.
My next mainstream technothriller was Dale Brown’s Flight of the Old Dog, a perfectly good choice. My first Tom Clancy was Red Storm Rising. The big crossover was the Survivalist novels, where the tiny thread connecting the po-faced technothrillers I’d read before to the ridiculous action excess that series revealed to me was that both were technically World War III novels.