In recent years, keeping political diaries has fallen out of fashion. I blame this on a young Clinton-era Treasury aide named Josh Steiner, whose private journal was subpoenaed in a long-forgotten scandal. Anyone interested in history will suffer for the decline of this art form (and no, blogging is not a substitute). To see what we may be missing in the future, consider the astonishing case of the late Arthur M. Schlesinger Jr. Shortly before he died earlier this year, he instructed two of his sons to prepare his diaries for publication. The resulting book, "Journals: 1952-2000," contains juicy morsels on every one of its 858 pages.