I was rather surprised to see Philip Klass appearing in the Daily Telegraph obituary column last week (2 March 2010) believing that lovable old Uncle Phil had died a couple of years ago. However this was not the curmudgeonly old skeptic that we at Magonia Mansions revere. Instead it turned out to be the real name of science fiction writer William Tenn. Curiously 'our' Phil Klass was for some time believed by some ufologists to be 'really' William Tenn (as well as being a CIA agent paid to debunk UFOs). Of course, at one time 'William Tenn' was thought to be a pen name of Tennessee Williams - not someone I would imagine writing science-fiction on his days off, but there you go.
To distinguish between them, consult this cut-out-and-keep guide:
Incidently, those who miss L. O. Uncle Phil's distinctive Skeptics' UFO Newsletter, will know that the tradition is being carried on by Tim Printy in the form of the on-line journal SUNLite, but without the master's characteristically deranged typography.