Just occasionally, a writer or artist, or both in one, emerges who is so astoundingly original that everything else suddenly seems like a facsimile of what has come before. Chris Ware, the 45-year-old American comic artist, is one of these. Widely hailed as one of the foremost practitioners working in the medium today, his new book, if one can call it that without being reductionist, is a work of such startling genius that it is difficult to know where to begin.