Early years : 1900-1913 -- Great War and its aftermath : 1914-1929 -- Depression years : 1930-1939 -- Days of infamy and a new era : 1940-1949 -- Laying the groundwork for change : 1950-1959 -- Turbulent sixties : 1960-1969 -- Changing times, changing roles : 1970-1979 -- Redefining practice : 1980-1989 -- Nineties : anticipating the new millennium.