The latest addition--succeeding The Irony of It All (1986)-- to the projected four-volume survey of 20th-century American religion by the well-known Univ. of Chicago historian (Religion and the Republic, 1987; Pilgrims in Their Own Land, 1984, etc.). ``Will America remain Protestant and Anglo-Saxon?'' According to Marty, this was the central question of the period between the world wars, posed by old-stock Americans and immigrant newcomers alike. Marty sees many of the distinctive movements of these years--the Red scare, labor-union unrest, Prohibition, nativism--as reactions of a native-born (and usually provincial) populace that feared the incipient power of the new ethnic groups. The arrival of Catholics and Jews in great numbers during the 19th and early 20th centuries threatened the privileged position of the Protestant churches in public life, and elicited such disparate responses as ecumenism, the ``Social Gospel,'' and the Ku Klux Klan. Marty is at his best when writing from the perspective of the Protestant majority (as in his account of the struggle between the ``modernist'' and the ``fundamentalist'' sects), but he does not limit himself to the experience of those churches--and gives, for example, a fascinating history of the Zionist movement among American Jews. He is far less sure of himself when covering the development of Catholicism during this period, however, and pays almost no attention to the Orthodox churches. Comprehensive and readable, but lacking depth: scholars will find surprisingly little analysis, and no new insights.