A long, uninspired chronicle of a grand unconsummated passion: Tehan, who has also written a life of Cardinal Gibbons, takes over 300 densely detailed pages to flesh out Bernard Berenson's summary judgment that ""Lizzie Cameron was the material, if not the spiritual, center of Adams's existence for the last 30 years of his life."" Several generations of American and European socialites agreed that Cameron (1857-1944), the niece of Gen. William T. Sherman, was a beautiful, charming, and intelligent woman. She had the misfortune, however, to be dragooned at 20 into a loveless marriage with Senator Don Cameron (R--Pa.), a wealthy lout more than twice her age; and while she looked to other men for emotional and intellectual sustenance, she never--except, perhaps, with the handsome young poet-scholar Joe Stickney--went beyond the limits of married propriety. Adams seems to have been fascinated by Mrs. Cameron even before his own wife, Marian Hooper (""Clover""), poisoned herself in 1885 and left him devastated for the rest of his days. His subsequent love for the Senator's estranged wife became an enduring tragicomic obsession (Adams called himself her ""tame cat""), which we can now follow from Washington to the Fiji Islands to Paris, thanks to Tehan's exhaustive research. But the endless minutiae of this platonic affair--parties, travels, letters, conversations--never cohere into a flowing narrative. Tehan never presents a clear-cut picture or probing analysis of Mrs. Cameron. (Characteristically, she quotes without comment a Cameron note to Adams with the absurd canard that Maupassant was the son of Flaubert.) Readers will be left wondering if this vivacious, highly decorative lady was worth all Adams's trouble--assuming they have the patience to hear out the slow-moving particulars.