Every now and then one receives a letter that leaves one in little doubt that the sender is more than a little grumpy. Take this e-mail from an academic to one of our reporters: "Truly you live up to the normal excremental description of the journalist. I want nothing to do with you ever again." Ah, yes. All perfectly clear, thank you. That is, until the sender decided that the same "excremental" journalist might actually be useful to him, and wrote again requesting assistance in putting some controversial information into the public domain. "All previous insults are inoperative," the academic added. "I didn't think, then, that I needed your help."