In spite of some ignorant claims of James White (see below) Martin Luther (1483-1546) always held to the doctrine of Baptismal Regeneration. I just recently found a PhD dissertation on Luther's theology of baptism published by the University of Durham:
Jonathan
D. Trigg, Baptism in the theology of Martin Luther simper ES in Motu Et Initio (1991)
The
book, Baptism
in the Theology of Martin Luther, was based on this doctoral
dissertation, although it costs an arm and a leg, so I have not read it (though
if anyone wants to gift me a copy, I will not complain . . . )
As
an aside, a great video refuting James White on Luther's theology of baptism,
particularly baptismal regeneration, can be seen in the following video with
Christian Wagner (RC) and Jack Lin (Lutheran):
A Lutheran and I Take Down James White on Baptismal Regeneration