Often described as an emergency, homelessness in America is becoming a chronic condition that reflects an overall decline in the nation's standard of living and the general state of the economy. This is the disturbing conclusion drawn by Martha Burt in Over the Edge, a timely book that takes a clear-eyed look at the astonishing surge in the homeless population during the 1980s.

Assembling and analyzing data from 147 U.S. cities, Burt documents the increase in homelessness and proposes a comprehensive explanation of its causes, incorporating economic, personal, and policy determinants. Her unique research answers many provocative questions: Why did homelessness continue to spiral even after economic conditions improved in 1983? Why is it significantly greater in cities with both high poverty rates and high per capita income? What can be done about the problem?

Burt points to the significant catalysts of homelessness—the decline of manufacturing jobs in the inner city, the increased cost of living, the tight rental housing market, diminished household income, and reductions in public benefit programs—all of which exert pressures on the more vulnerable of the extremely poor. She looks at the special problems facing the homeless, including the growing number of mentally ill and chemically dependent individuals, and explains why certain groups—minorities and low-skilled men, single men and women, and families headed by women—are at greatest risk of becoming homeless. Burt's analysis reveals that homelessness arises from no single factor, but is instead perpetuated by pivotal interactions between external social and economic conditions and personal vulnerabilities.

From an understanding of these interactions, Over the Edge builds lucid, realistic recommendations for policymakers struggling to alleviate a situation of grave consequence for our entire society.

MARTHA R. BURT is director of the Social Services Research Program at the Urban Institute.

Just as famines and plagues can provide opportunities for medical research, the unhappy course of United States relations with Vietnam is a prime source of evidence for students of American political institutions. How Presidents Test Reality draws on the record of American decision making about Vietnam to explore the capacity of top government executives and their advisers to engage in effective reality testing.

Authors Burke and Greenstein compare the Vietnam decisions of two presidents whose leadership styles and advisory systems diverged as sharply as any in the modern presidency. Faced with a common challenge—an incipient Communist take-over of Vietnam—presidents Eisenhower and Johnson engaged in intense debates with their aides and associates, some of whom favored intervention and some of whom opposed it. In the Dien Bien Phu Crisis of 1954, Eisenhower decided not to enter the conflict; in 1965, when it became evident that the regime in South Vietnam could not hold out much longer, Johnson intervened.

How Presidents Test Reality uses declassified records and interviews with participants to assess the adequacy of each president’s use of advice and information. This important book advances our historical understanding of the American involvement in Vietnam and illuminates the preconditions of effective presidential leadership in the modern world.

"An exceptionally thoughtful exercise in what ‘contemporary history’ ought to be. Illuminates the past in a way that suggests how we might deal with the present and the future." —John Lewis Gaddis

"Burke and Greenstein have written what amounts to an owner's manual for operating the National Security Council....This is a book Reagan's people could have used and George Bush ought to read." —Bob Schieffer, The Washington Monthly

JOHN P. BURKE is associate professor of political science at the University of Vermont.

FRED I. GREENSTEIN is professor of politics at Princeton University and director of the Program in Leadership Studies at the Woodrow Wilson School of Public and International Affairs.