Philomena and her twin brother Colum were born in Illinois, United States, of an Irish mother and American father.
[4] She moved to the United States to study geology at Princeton University in 1973,[1] graduating in 1978.
[9] Both Philomena and Colum played in the post-punk rock band Cruella de Ville, formed in 1982.
[10][11][12][13][14] As of 2011, Muinzer was working as public relations officer for Pennant Books in London.
[16] Muinzer has written several plays and at least two books, sometimes adopting the pseudonym Phil O'Brien (O'Brien being the Munizers' mother's maiden name[2]): She was married to writer Colin Bennett until his death on 15 February 2015.