POVERTY AND INJUSTICE are rarely sufficient to provoke people to revolt. Most individuals prefer to adapt to authority rather than to run the risks incurred in confrontation. Yet, in Nicaragua in 1978-79 the population finally rose up and overthrew the hemisphere's oldest dictatorship.

The causes were several. Even though the country had experienced a period of economic growth, inflation was eating into the already low living standards of urban workers and peasants. Frustration was especially high among the burgeoning population of underemployed youth. Business and the Church, once pillars of the ancien regime, had moved into opposition. In addition, international opinion had momentarily become more sympathetic to political movements opposing authoritarian governments.

The essential motivation, however, was moral outrage at the degeneracy, corruption and brutality of the Somoza regime. The three books reviewed here, all by journalists who personally experienced the revolution, seek to communicate the depth of the popular rejection of the Somozas. Each author makes the case that the Somozas, whether or not they were "moderately repressive" in comparison to other dictators, had robbed the Nicaraguans of their freedom and dignity, and deserved their fate.

In Somoza, Bernard Diederich, a veteran Latin American correspondent with Time sketches the history of the dynasty from its creation in the 1930s by Tacho I, through the assassination of his exiled son Tacho II in 1980. Diederich's Somozas are fat from debauchery, bullies to their lackeys, scornful of their countrymen, and greedy without limits. Identifying private gain with the public welfare, they ran Nicaragua as though it were their own private estate.

What Diederich fails to explain adequately, however, is how the Somozas were able to retain power for over 40 years. While perhaps the least politically adept of the Somoza line, Tacho II was still an imposing presence. As a Latin Americanist in Carter's State Department, in 1978 I had a lengthy interview with the Nicaraguan president, and was left, at the end, thoroughly exhausted. Somoza's energy was that of a megalomaniac, but also of a quick mind, a born executive and a natural thespian. At one point, he jumped to his feet and pretended to draw a sword as he heaped abuse and threats on his foes, only to sit down quickly and resume more normal discourse. Diederich does not get quite close enough to Somoza to flush out these traits of mental imbalance and of leadership.

Diederich drubs U.S. policy for its long-standing support of the Somozas, a policy started by FDR, who reportedly said to Tacho I, "He's a sonofabitch, but he's ours." Diederich welcomed Carter's human rights policies, but he argues that Carter was too slow to break decisively with Somoza. Carter's last-minute efforts to preserve Somoza's army appear unworthy and unrealistic. Diederich does not, however, attempt to investigate the inner deliberations of the Washington bureaucracy, or debate the government's available options.

Somoza is a highly readable introduction to recent Nicaraguan history. The eyewitness reporting on the final insurrection is especially compelling. But the book is disappointingly short of new materials, and is stronger on description than analysis. The definitive history of the Nicaraguan revolution has yet to be written.

Richard Elman, a New York writer who briefly visited Nicaragua during and just after the revolution, is not a Nicaraguan expert, but he does have a talent for capturing moods and encapsulating the human predicament. A collection of short vignettes, Cocktails at Somoza's is essentially about how different people react in an environment of political repression and violence. In the story which gives the book its title, Elman mixes fantasy and reality to ridicule Somoza's pretense that all was still normal in Nicaragua during the deluge. In other scenes, prosperous Somocistas express their annoyance at the daily inconveniences occasioned by the civil strife. Elman doesn't sketch any seasoned guerrillas, but he presents a middle-class intellectual, Marco, who explains his moral reasons for joining the rebellion. Others join to avenge their fallen friends and relatives. Some become paralyzed with fear or bewilderment.

Cocktails is also about the difficulties liberal Americans can have in relating to Third World revolutions. Elman very much wants to be accepted and involved, yet he is uncomfortable with the Sandinistas, whose authoritarianism is inimical to his self-defined democratic socialist sensibilities. Moreover, Elman realizes that the struggle is, ultimately, not his own. He can always return to the cocktail lounge in his Managua hotel. In a telling scene, Elman is offered a ride on the back of a Sandinista's pickup truck that turns out to be carrying the decomposing body of a slain comrade. As if to express solidarity, he tries to withstand the stench, but finally decides to jump off and take a bus.

Nicaragua is a photojournalist's essay composed of 71 carefully chosen color photgraphs shot during the revolution. The book does not chronicle the main events, political formations or famous personalities of the period. Rather, photographer Susan Meiselas explores, with considerable sensitivity and technical skill, the emotions of ordinary combatants and civilians as the struggle builds from spontaneous insurrection to full-scale civil war leading to popular victory.

The photo of Somoza decked out in a white suit, black tie and presidential sash, followed by sunglassed aides, brilliantly captures the gangsterism of the anachronistic dynasty. The next photo reveals the ultimate source of the regime's power -- the camaraderie of the Somozas' praetorian army.

Meiselas sees popular violence as a gut response to Somoza's brutality, and rage as the product of intensifying repression. Her photos argue implicitly that the violence of the guerrillas is justified since they enjoy mass support, while the army is isolated from the angry population.

Meiselas, however, does not glorify revolution. In the appendix, composed of a chronology and quotes from Nicaraguans, she cites Carlos Fonseca, martyred founder of the Sandinistas: "Victory has a price both costly and sad." The photos of atrocities and urban devastation are painful and sometimes nauseating. Moreover, Meiselas seems concerned that the cult of violence could be hard to shake. For example, one photo shows a child admiring a guerrilla's rifle. Nevertheless, the people seem willing to pay the price; Nicaraguans from all social classes are depicted providing support to the rebels.

Like Deiderich and Elman, Meiselas clearly believes that when a people are burdened with a depraved despotism lacking all moral authority, armed revolt is a legitimate means for the reassertion of human dignity.