AD is a useful trick to compute derivatives as part of some algorithm that needs to compute them.
Leibniz 1664 was the first and AD has been used in fluid flow engineering years before finance.Some recent articles on ANN (e.g. McGhee) discard AD in favour of cublc splines, which is a bit weird..AD is in its infancy, manually is error-prone and scales badly. I've read somewhere (Pearlmutter)
AFAIR Mike Giles in 2006 introduced it.
The 1st PhD on AD was Wengert 1964.
And then there's the Complex Step Method which quants don't use?