1922 - The first issue of The Journal for Personnel Research is published by the Personnel Research Foundation.
1923 - President Warren Harding, left, dies in office; Vice President Calvin Coolidge is sworn in as president.
1924 - Hawthorne Effect studies, shown at right, begin, showed workers were more productive when they thought they were being studied.
1925 - The Brotherhood of Sleeping Car Porters, above, the first U.S. labor group led by African-Americans, is formed.
1927 - First transatlantic telephone call is made between New York and London. Incidentally, the first "videophone" call took place in April of that year.
1929 - Herbert Hoover, left, is sworn in as president of the United States.
1929 - Stock market crashes, which starts the Great Depression.
1932 - Police open fire at 3,000 unemployed auto workers marching at the Ford River Rouge Plant in Dearborn, Michigan, killing four people.
1932 - Franklin Delano Roosevelt is sworn in as president.
1933 - Frances Perkins, above, becomes secretary of labor; she is the first woman to be named to a presidential Cabinet.
1935 - FDR signs Social Security and National Labor Relations acts into law.
1936 - The United Auto Workers organized the Flint Sit-Down Strike, which helps propel the UAW's national exposure.
1938 - Congress passes the Fair Labor Standards Act establishing the 40-hour workweek and minimum wage, and banning child labor.
1941 - U.S. officially enters World War II after Japan attacks Pearl Harbor, right.
1942 - The song Rosie the Riveter is released. The name catches on and becomes a symbol for women working in factories during World War II.
1944 - 1945 - World War II ends. Between November 1944 and September 1945, U.S. employment drops by 4.3 million.
1945 - Vice President Harry Truman is sworn in as president when FDR dies in office.
1946 - The first electronic digital computer, known as ENIAC, is introduced. It takes up an entire room.
1946 - Baby boomer generation begins.
1946 - President Truman signs Executive Order 9981, which eliminates segregation in the U.S. military.
1948 - The American Society for Personnel Administration is founded. The group later changes its name to the Society for Human Resource Management.
1953 - Dwight Eisenhower becomes president.
1955 - Ray Kroc founds McDonald's Corp. Five years later Kroc would buy exclusive rights to the McDonald's name and help oversee its worldwide expansion.
1956 - Eisenhower signs the Federal-Aid Highway Act, which creates the Interstate Highway System.
1957 - The FBI arrests Teamster leader Jimmy Hoffa and charges him with bribery.
1960 - First civil rights sit-in takes place at a Woolworth's food counter in Greensboro, North Carolina.
1961 - John F. Kennedy is sworn in as president.
Generation X begins in the early 1960s.
1962 - Sam Walton opens his first Wal-Mart store in Rogers, Arkansas. Today, the company is the world's largest private employer.
1963 - The Feminine Mystique by Betty Friedan, above, is published, sparking a new wave of feminism in the U.S.
1963 -JFK is assassinated; Vice President Lyndon Johnson is sworn in as president. …