Louise GlUck has long practiced poetry as a species of clairvoyance. She began as Cassandra, at a distance, in league with the immortal; to read her books sequentially is to chart the oracle's metamorphosis into unwilling vessel, reckless, mortal, and crude. "The Seven Ages" is GlUck's ninth book, her strangest and most bold. In it she stares down her own death, and, in so doing, forces endless superimpositions of the possible on the impossible -- an act that simultaneously defies and embraces the inevitable, and is, finally, mimetic. Over and over, at each wild leap or transformation, flames shoot up the reader's spine.