More has been written on Martin Luther than any other figure in Church History. He stands between the medieval and modern worlds, and on one of the great faultlines of Christianity, and his thinking defines protestant theology to this day.
Lots of good online media on the subject. Melvin Bragg on Radio 4’s ‘In our time’ discussing Luther at the Diet of Worms. There is the webpage of a US TV series on Luther with a dramatic introduction to the man and some interviews with people including Alistar McGrath. An interesting listen is David Starkey’s abject attempt to suggest that Luther killed christianity which is shot down by his own witnesses.