Most historians probably have a good idea of their central thesis even before they begin the laborious spadework of research.

But for British Jewish historian Paul Bogdanor, his ambition to find material defending the controversial wartime Zionist leader, Rudolf Kasztner, was cruelly thwarted.

Bogdanor was “extremely shocked” to find that everything pointed towards Kasztner’s having been “a collaborator” with the Nazis, and a “betrayer of the Zionist movement and the Jewish people.”

Bogdanor’s new book, “Kasztner’s Crime,” published in October, sets out the case against the Jewish leader in damning detail. Even the most devoted defender might have second thoughts after reading his book.

Ironically, Bogdanor set out to work on the book almost a decade ago in a bid “to prove Kasztner’s innocence.” He was tired of seeing Kasztner’s name come up repeatedly in anti-Zionist propaganda.

Kasztner was a leader of a small Zionist grouping in Budapest towards the end of World War II. He led a Jewish rescue committee which, before the Nazis entered Hungary, did succeed in saving the lives of a number of Jews. But once the Nazis arrived, Kasztner, an ambitious lawyer, became embroiled in prolonged negotiations with the Nazi leadership, particularly Adolf Eichmann. ...