The3rd Earl Of Derby wrote:
I've been given a set of four 120 year old panelled doors which I've
stripped off the paint down to the bare wood.

Looking down the length of one, the lock side it has become warped(bowing)
is it possible to straighten this warping out?
....

Fisette, Paul. "Straightening a Warped Door.", On The House column in
Journal of Light Construction, June 1999, 19-20.

I recall it, unfortunately columns aren't archived online.

Basically, if it can be done, it is a combination of moisture and
force.

Knowing which way it is warped (a twist the length of the door, the
middle bowed out, combination, something else) and the type of wood and
construction (solid/veneer/combination/dimensions/how much
distortion/etc.) would help.