Eric Alterman criticizes my recent commentary in The Sun on major media bias ("Liberal media bias is beyond doubt, March 18) because, he claims, I lacked "supporting evidence" in claiming his book, ""What Liberal Media? The Truth About Bias and the News," had "evidentiary problems" ("Vatz's baseless attack," March 21). He unsurprisingly quotes variously liberal sources as finding his thesis well-proved. In several e-mails to me, he recklessly analogized me to the reckless Joe McCarthy, ending with addressing me as "Joe." Very adult.