Part Two, "Classics," is the largest part of the book, 300 of its 500 pages, but not the most interesting. Lucid, knowledgeable, gracefully written accounts of major figures in painting and sculpture, music and dance, literature, architecture, drama and film -- very nice, but if you know anything about the history of these arts in the late 19th and early 20th centuries, this is the stuff you already know.
Parts One ("Founders") and Three ("Endings") made the book memorable for me, precisely because these sections on the historical circumstances and cultural connections of modernism have to do with matters Gay, an historian of staggering erudition in the arts and culture, is uniquely qualified to describe. Patronage gets a lot more attention here than in other accounts of modernism, as does the role of certain crucial critics as official exegetes/publicists for art that was doing its damnedest to be unassimilable to any known canons of taste. This is a much more situated & contextualized account of modernism than we usually get. Gay also says some very apt things about modernism and the rise of totalitarianism.
I was a bit let down, however, by the final chapter, "Life After Death?". Gay argues that modernism was basically finished by 1960 or so -- fair enough -- but seems to think that means there was little art of interest after this date. He likes Garcia Marquez and Grass and Gehry -- again, fair enough -- but finds little else to admire in the art of the last 40 or 50 years. Consider this, from p. 499: "But it is true that nowadays there are virtually no novelists whose announcement of a new work of fiction would make lovers of high literature rush out to a bookstore and buy it."
Maybe I'm not a "lover of high literature" -- though I read and love Flaubert, Joyce, Kafka, Woolf, Proust, Mann, and the other modernist novelists Gay gives particular attention to -- but there are actually quite a few novelists whose new novels I acquire as soon as they appear and read as promptly as I can manage.
In no particular order: Paul Auster, Philip Roth, Margaret Atwood, Toni Morrison, Ben Marcus, Don DeLillo, Edmund White, Thomas Pynchon, David Foster Wallace, Shirley Hazzard, Mary Gaitskill, John Banville, Salman Rushdie...
It does not seem to me that we are in a slack time for literature at all, either in fiction or in poetry. Or in music (Steve Reich) or dance (Mark Morris) or painting (Anselm Kiefer) either, for that matter.