During the 1950s his calculations of the harmful effects of  radioactive fallout led him to become the leading
American scientist in the campaign to increase awareness of the perils of atomic weapons & the holocaust
of an atomic war.  His petition to the United Nations against the testing of nuclear bombs was signed by
more than 11,000 of the world's scientists from 49 countries on both sides of the "Iron Curtain." 
In 1960 when the US Senate Internal Security Sub-Committee accused him of "a consistent pro Soviet bias,"
he risked  jail for contempt of Congress by refusing to reveal the names of the scientists who'd helped
gather signatures.  Denying under oath that he'd ever been a Communist, he repeated his famous 1950
declaration: The problem of an atomic war must not be confused by minor problems such as Communism versus Capitalism.
His efforts contributed significantly to President Kennedy's decision, shortly before JFK's assassination, 
to sign the 1963 Atmospheric Nuclear Weapons Test Ban Accord.  That same year Dr. Pauling was notified
that he'd been awarded the 1962 Noble Peace Prize -  the second double Nobel Laureate since Madame
Marie Curie, the discoverer of radium. 
In his later years he researched the molecular nature of mental illness & the role of vitamin-C in
strengthening the immune system.  Dedicated to utilizing science in the service of humanity, & acclaimed 
as one of  the leading analytical minds of the 20th Century, he passed away in 1994.

                             Some of these photos are in the CalTech & Oregon State University Pauling Archives
                                                          Click photo for Gallery view