Jonestown and after; White Night, by John Peer Nugent. New York: Rawson, Wade. $11.95.

In the weeks following the November 1978 mass suicide and murder in Jonestown , Guyana, a handful of paperback publishers rushed into print with potboilers attempting to explain the "full story" about cult leader Jim Jones and his sad following.

Such efforts were little more than compilations of newsclips and hastily gained impressions from those who shortly before (like the rest of the world) barely knew where Guyana was. Superficial and sensationalistic, they barely scratched the surface of this American tragedy.

There was, in fact, a tragic inevitability about the Jonestown story, and in this regard John Peer Nugent has rendered a valuable -- if painful -- service. A veteran foreign correspondent specializing in the third world, he brings a longer view that is necessary to understand the "why?" of Jonestown, a view that must precede efforts to prevent anything like it happening again.

Mr. Nugent's thesis is that American foreign policy decisions made years ago contributed directly to Guyana's being ripe for a Jim Jones to settle there. the hand of the US Central Intelligence Agency was heavy in Guyana, just as it was in Cuba and later in Chile. Times changed, but the government there became no less inefficient, hanging on to vestiges of British colonialism even as it spouted anti-American rhetoric.

In reading "White Night" (Jone's term for the massive Peoples Temple suicide) , one wants to scream out at those in authority who seem so oblivious to what was happening: the local officials in California who cozyed up to Jones for the political support he could generate; national leaders (including Rosalynn Carter and Walter Mondale) who offered public endorsements of a madman they had barely met; experienced reporters and editors who certainly should have known better, but were taken in by "the Rev." Jones's supposed good works and popular leftward tilt.

Most of all, one stands in sad incomprehensibility at the more than 900 Peoples Temple members (one-third of them children) who lovingly addressed as "Dad" a man who in retrospect seems so obviously to have been sexually perverted , drug-dependent, and paranoid, a modern-day Father Divine who rejected the Bible and any sense of spirituality.

There is a controlled seething to Nugent's writing as he describes how the State Department in Washington, as well as the US Embassy and consulate in Guyana, either ignored or impotently wrung hands over the increasing reports about brainwashing, child abuse, and suicide drills in Jonestown. As critical reports from the State Department and a congressional committee later confirmed, this was known months before the jungle holocaust.

Since this book was written, cult experts report that such groups not only are spreading in the US and Europe, but are intensifying their recruiting activities and harrassment of scholars, lawyers, and physicians trying to help cult members.

One would like to think that the lesson of the People Temple and Jonestown has been learned, but the facts seem to indicate otherwise. Rep. Bill Royer (R) of California, who succeeded the late Congressman Leo Ryan (killed at Jonestown) , finds the lack of follow- up action by federal agencies "appalling." This book helps remind us that the Jonestown story is not yet finished.