This last volume of Adlai Stevenson's papers, covering his frustrated, often forlorn years as American Ambassador to the UN, is something of a disappointment--lots of social notes, few significant documents. As editor Johnson remarks, much material remains classified. And, too, John Bartlow Martin has already excerpted the key passages in his monumental biography. One does, however, re-experience Stevenson's strained relations with JFK (""I don't believe I was indiscreet but if I was I ask your forgiveness""); the humiliation of his denial of U.S. involvement in the Bay of Pigs invasion, the countervailing triumph of his hell-freezes-over speech in the Cuban missile crisis; his persistent support of a policy favoring ""our future relations with the people of Africa"" (apropos, in 1963, of Portuguese territories); and--via the reports of his petitioners--his misgivings about American policy in Vietnam coupled with his disinclination to voice them publicly. (""No, I will not resign. I would never take advantage of my political position to resign for political reasons. That's not the way we play the game."") Meanwhile he keeps tabs on a host of friends and relations, and the several ladies in his life (playful missives to Alicia Patterson, poetry and laments to Marietta Tree); and refers frequently to the ""sad sadder saddest story"" of Ellen, his divorced, disturbed wife. An appropriately graceful tribute by Eric Sevareid concludes.