Kenneth Koch, who has already considerably "stretched our ideas of what it is possible to do in poetry" (David Lehman), here takes on the classic poetic device of apostrophe, or direct address. His use of it gives him yet another chance to say things never said before in prose or in verse and, as well, to bring new life to a form in which Donne talked to Death, Shelley to the West Wind, Whitman to the Earth, Pound to his Songs, O'Hara to the Sun at Fire Island.   Koch, in this new book, talks to things important in his life -- to Breath, to World War Two, to Orgasms, to the French Language, to Jewishness, to Psychoanalysis, to Sleep, to his Heart, to Friendship, to High Spirits, to his Twenties, to the Unknown. He makes of all these "new addresses" an exhilarating autobiography of a most surprising and unforeseeable kind.