At the outset it should be made dear that this is an extremely old-fashioned, not to say anachronistic book. Like Alexis de Tocqueville, on whom he has written a book, Pierson, a Yale historian, is an essayist endeavoring to delineate that ineffable and somewhat discredited abstraction -- the American Character. The key, as Pierson sees it, lies in the ""M-Factor"" -- the American propensity for ""movement, migration, mobility."" To assess its impact, Pierson calls in a great array of 19th-century observers of the American scene, everyone from de Tocqueville to Dickens -- to say nothing of the Americans themselves. Whitman sang of the open road, Greeley urged ""Go West Young Man,"" Hawthorne and James Whitcomb Riley and Steinbeck and many, many others noted our ""vagabond habits."" in proverb and slang, says Pierson, we have always equated horizontal movement with vertical ascent: the successful person is ""going places,"" he's an ""up-and-comer."" Lingering over our immigrant heritage Pierson sweeps over Turner's frontier thesis, tourism, the cult of the automobile, the boom growth of Florida and California, the mobile home industry. He believes the repercussions of all this wanderlust have had an enormous social and psychic effect. Like Turner he subscribes to the safety valve notion -- the idea that the great open spaces siphoned off the discontented and the rebellious, the desperados and agitators. He further argues that uprooting, by severing the individual from his ""social envelope,"" stimulated the growth of the ""joiner personality,"" the hail-fellow-well-met gregariousness, egalitarianism and much else. And yet, unlike Vance Packard (A Nation of Strangers, p. 781) Pierson avoids analysis of the effects of migration and relocation on a single community, family or individual. Sociological methods are not for him; he doesn't hesitate to generalize wildly on the basis of casual, subjective impressions -- frequently gleaned from poesy and literature. Also, unlike Packard, he's an optimist: the M-Factor has helped make us free, independent, resourceful, tolerant of others. Nothing here of the anomie, the mistrustfulness, the lonely hedonism which so disturbed Packard. In sum, this is an impressionistic panorama; those who wish a more rigorous overview of the nomadic compulsion in American life today will do better reading A Nation of Strangers.