Two people emailed me in response to my recent post about the use of pseudonyms and whether or not journalists and reviewers have a responsibility to protect the authors' true identities.
I wrote that, in most cases, I didn't think there is an obligation to keep the secret. When I made that statement, I had in mind the recent trend in publishing where authors use pseudonyms either for marketing purposes or to "trick" the chain store buyers.
In that case, assuming that the author's true identity is somehow relevant to what I'm writing, I would not feel obligated to play along.
However, in the case of authors who use a dedicated pseudonym (i.e., they always write under the same alias) or authors who must cloak their identities for legitimate reasons, there would likely be no reason to discuss the author's real name or identity.
As one of my correspondents wrote, "Before revealing the writer's real name, it's the journalist's obligation to think through the consequences." Good point.
Ultimately, it comes down to relevance. Is the author's use of a pseudonym relevant to the discussion or critique of the book? If not, then mentioning it would not be appropriate.