Boom ripple through the economy with unpredictable conse-quences. The biggest recent shift: an enormous increase in the number and proportion of women in the workforce, especially married women, that shows no sign of letting up. This develop- ment alone, claims Columbia's Eli Ginzburg, will change modern American society "more than the rise of communism or the harnessing of nuclear power." Perhaps. Economists' views vary. Here, Richard Freeman looks at the evolving "shape" of...