Accustomed as we have been to periodizing history into decades, we're in for some confusion now: What are we supposed to call this decade? The zeroes? The Os? The aughts? We have no precedents to guide us, since nobody in the past century seems to have spoken in terms of decades until the 1920s, or really until the 1930s, when people began to look back on something they called the 1920s. History, we've come to believe, occurs naturally in 10-year units. We even assume that decades possess their own agency--David Frum subtitles How We Got Here, his new book on the 1970s, The Decade That Brought You Modern Life. Where will we be if we can't properly label the '00s?