Lawrance Thompson, the authorized biographer of Robert Frost, waited almost twenty-five years to fulfill his commission and then died before completing it. Frost was sixty-five when he invited Thompson to become his official biographer; little did either man realize that Frost would live to be eighty-eight. Frost stipulated that no biography was to be published during his life; since he faithfully honored Frost's request--as some other biographers did not--Thompson spent practically his whole career waiting to begin it. This waiting period did give Thompson time and leisure seldom accorded biographers--time enough, as Frost once wrote him, to find that "special phrase" to "get me by." Some critics suggest that Frost appointed Thompson his biographer to keep at bay the snooping that he disliked so much: an "official biographer" would permit him more readily to turn aside other requests. If this was Frost's plan, he lived long enough to...