V. S. Naipaul wanders the post-colonial world; The Return of Eva Peron with The Killings in Trinidad, by V. S. Naipaul. New York: Alfred A. Knopf. $10.

These four essays by the well-known West Indian writer are like marvelous conversations with a perceptive traveler in both the literary and developing worlds.

Like good conversation they flow easily. IF lacking facts, the essays are filled with focused intuitions and impressions. Some insights hit the reader so suddenly and penetrate so deeply that he cannot doubt their accuracy.

Like conversations these essays also meander where they will, but the author always pulls them back to the point. Sometimes they are overextended, sometimes repetitous. And sometimes, when the reader knows the territory as well as or better than Naipaul, he recognizes factual inaccuracies and weaknesses of analysis. Even so, the essays are written with such grace that a reader's indulgence seems assured.

The first three essays meditate on conditions in the post-colonial world in the first years of the '70s. The fourth is an appreciation of Joseph Conrad, whose value to Naipaul "is that he is someone who sixty or seventy years ago meditated on a world I recognize today."

The title essay strikes me as the most successful. It is Naipaul's attempt to understand Argentina.

He looks at its "bogus past," sees after the six-year extermination of the Indians the appearance of "vast estanciasm on the stolen, bloody land: a sudden and jealous colonial aristocracy." He examines the uneasy relationship between that aristocracy and the urban immigrants, between Buenos Aires and the pampa which supports its high style, between the Argentina with their yearning for a European culture and the physical, historical, cultural reality of the land they live on. For Naipaul, Eva Peron acted as the catalyst which forced these uneasy relationships to degenerate into terror.

"The Killings in Trinidad" offers an insightful portrait of a Trinidadian of mixed race who exploited London media interest in black power to become "Michael X." His pretensions to power and destiny -- which Naipul regards as a modern Stepin Fetchit routine -- led to the man's insanity and execution following two pointless murders.

Such is Naipaul's skill that he invests this material with more significance than it at first seems likely to yield. For that reason it is curiously disappointing, on finishing the essay, to feel that the material seemed better than the author's treatment of it.

As with the title essay, "A New King for the Congo: Mobutu and the Nihilism of Africa" is Naipaul's attempt to understand a developing country still wrestling with the effects of colonialism. As always, it's beautifully crafted. But Naipaul seems to have spent only three months in the country, and as analysis the essay strikes me as decidedly lightweight. Having lived in provincial outposts of the Congo, now Zaire, for two years during some of the events Naipaul's essay describes, the factual lapses here are unsettling, though perhaps not damaging to the thrust of analysis. Still, they do raise questions about the foundations on which this essay and the others rest.

Simply stated, the essay's core idea is that a century after King Leopold's rape of the Congo, it is black men, not whites, who now embrace "nihilism." Unlike Conrad's ivory agent, Kurtz, "degraded from idealism to savagery" in "The Heart of Darkness" because of his contact with "wilderness, solitude, primitivism and power," it is now the African who has been "maddened" through contact "with the civilization established by (King Leopold's) pioneers."

This is a neat literacy reversal, beautifully set forth. But their-savagery-debased-us-our-civilization-debased-them hardly qualifies as the kind of insight we've learned to expect from this author.

Some years from now there is a wonderful essay to be written about how and why Joseph Mobutu, who once seemed the hope of the Congo, grew into Mobuto Sese Seko, that Zairean symbol of corruption. One hopes that the person who tackles it writes with the craft and perception generally associated with V. S. Naipaul.