Magnum, P.I. was a TV series starring Tom Selleck as Thomas Magnum, a private investigator living on Oahu, Hawaii. The series ran from 1980 to 1988.    Magnum, P.I. was one of the highest-rated shows on U.S. television.    Thanks to Magnum, P.I., Hawaiian shirts sales soared (as did the numbers of men, of all walks of life, sporting mustaches).  Best looking guy on TV - still!