The size of Joshua Cohen’s achievement sank in only when he received an anonymous e-mail showing his head Photoshopped on to the body of a Jewish person being pushed into a Nazi gas chamber.

The writer, 41, had arrived in Israel last week to spend a few quiet days working on his next novel before an appearance at the Jerusalem International Book Forum. Then he got a surprising phone call from New York informing him that his latest novel, The Netanyahus: An Account of a Minor and Ultimately Even Negligible Episode in the History of a Very Famous Family, had just won the Pulitzer Prize for fiction.