Mr. Bear is smarter than this...

[ham]

I'm sure there is some highly embarrassing reason other than his wife's un-hyphenability that caused him to change his name, but I'm not sure this is it.

Jews changing name is as old as man.
However, one's heritage should make one proud.
To be honest, Klempner isn't much a pain compared with other Jewish names.

[Ben Johnson]

Could it be that Klempner just wasn't a very good screenwriter? Or at least not prolific enough to earn a consistent living? In some circles the notion of being "blacklisted" has an appealing revolutionary aura. It certainly sounds a lot more exciting than being "unemployed."

Come the 1960s, wasn't being a Jewish communist a recipe for success. Klempner Sr. lucked out a few times and instead of telling Klempner Jr. that he was a washed-out has-been told him he was blacklisted. Maybe Klempner Jr. invented the story because Dad the blcklisted writer is more appealing than Dad, the has-been writer/accountant. Maybe it's just like wearing medals you didn't earn.