For the facts of his life in newspaper form, combined with some decent editorializing about his larger meaning, see Charles McGrath in the New York Times, a paper that Vidal often complained failed to give him the attention he deseved as a novelist.
For his life story as told by him, see Palimpsests and Point to Point Navigation, with the former, earlier book more thorough and thoughtful; and I enjoyed though Vidal himself despised Fred Kaplan's Gore Vidal: A Biography.
Vidal was, and will still be in death, an object of reflexive contempt by most people who think of themselves "of the right," I think largely because of his personal contretemps with conservative leader William Buckley, though there is more to it than that, which I'll get to shortly.
My affection for his writing had much to do with a resonance with his spirit, especially its anger and contempt at empire and the national security state, and awe at his wit, in his essays at least. Vidal was more impressed with his own whimsies and absurdities and comedies in fiction than I was, though. His "comic" novels of the Myra Breckenridge and Duluth variety, when I can get through them at all, are my least favorite of his books, while as Nick Gillespie noted below, Vidal on at least one occasion called Duluth his favorite.
Bill Kauffman (who shares Vidal's interest in and possessive attitude toward the history of American letters and the American republic) reviewed in The American Conservative a Vidal essay collection and called him "The Last Republican" in the sense of admiring a small America that minded its own business and respected its citizens' rights. In it Kauffman makes the best case for the non-partisan conservative to admire Vidal.
Vidal's seven-novel series of American history, which he called "Narratives of Empire," are my favorite of his fictions and I recommend them highly for a never-didactic survey of a nation that is wounded by its government but still a glorious setting in which conflicted, striving, but admirable humans scheme and strain and dream and create, with a mordant and well-placed understanding of the seats of power, political and cultural, from the Founding Fathers to FDR. (Empire is my favorite, Washington D.C. least favorite, but they are all fine.)
My 2007Reason review of one of his memoirs, Point to Point Navigation, summed up some of my thoughts on him. He was at heart just a plain fascinating interesting character, not afraid to gossip about the other fascinating characters he interacted with in politics and culture (Kennedy and Tennessee Williams tales were his favorites), interested in people and writers and power and liberty; he wrote from where he came from and what he knew, growing up as he did in Washington, D.C., at the knee of his grandfather, the Sen. Thomas P. Gore (D-Okla.), who as Kauffman described him was "a first-rate populist foe of war and FDR. He was a peace Democrat, which is why no one has ever heard of him."
I reviewed his magisterial essay collection United States (a true top 10 desert island tome, over 1200 pages that bring the literary and historical world entire of our nation to you with the wittiest and most engaging of guides) in the March 1995 issue of Liberty, pairing Vidal's book with the latest essay collection of his old sparring partner William Buckley.
In that review I dealt with why so many on the Right have such a reflexive and unearned contempt for Vidal. I wrote: "Vidal's political instincts and opinions are sometimes admirable and sometimes goofy. He loves the Old Republic and can even find a good word of the likes of Pat Buchanan, 'a reactionary in the good sense--reacting against the empire in favor of the Old Republic.' Now, what other monotheism-hating queer would write that? Vidal is no libertarian, of course, and he is not particularly thoughtful or sensible on politics much of the time. He harbors a cliched aversion to the accumulation of wealth, seems to believe capitalism can only succeed by driving its workers into penury and quasi-slavery, and holds an affection for socialistic redistribution of income that is not practically compatible with his hatred for the national security state and for a government that, since Lincoln and Roosevelt, can get away with whatever it pleases."
Vidal "hated tyranny, but also seems to hate wealth and that which is often done to attain it. But he also hates empire and loves civilization, and praised its loveliness in his wide-ranging enthusiasms and joyous and witty expressions of admiration for so many things. One comes away from Vidal enriched and energized and inspired--to read the author he has been discussing, to ponder his interpretations, to learn more about his topic."
As a critic, Vidal added greatly to my own mental life by being a sympathetic and knowing introduction to the novels of Louis Auchincloss and Dawn Powell and the works of Montaigne and Anthony Powell. Vidal had a winning mistrust of elites and understood--and this is the key to why so many cannot tolerate him--that they, especially in the American security and foreign policy apparati, didn't necessarily mean well and could and did behave evilly.
This is not a message many Americans can handle (as Ron Paul has learned), but one they ought to hear. Combined with that understanding of the malignities of empire was a mistrust of the means most of us learn about and understand the world, the modern media. I have often had occasion to think on Vidal's comment, "To take at face value any newspaper story is to be dangerously innocent. But one can't challenge everything that has ever been printed. So, through weariness and ignorance, there is a general consensus, which then becomes what I call an 'agreed-upon' fact. We all decide not to worry it."
That mentality which led Vidal to entertain heretical ideas such as that Timothy McVeigh had something more to him than insane monster, that the official story of 9/11 might not be entirely true, arises from Vidal's understanding that men of power can and do behave monstrously, yes even in America--his love of country was never blind. When I saw him speak in Los Angeles sometime I believe in the late 1990s, he was asked a question about party politics, and said merely, with no elaboration, "I'm partial to the Libertarians."
This libertarian was partial to him. I approached him for an interview for Reason in the early 2000s; at that point he insisted on having a list of questions faxed to him, which he might answer in writing, or possibly agree to meet. Eager to make sure the questions captured, as best they could, the rhythms of conversation, I overwrote the questions, with followups designed to capture and steer the flow of the "conversation" whichever way it might meander. The document probably read like a "choose your own adventure" book. I received an unexpected call from Vidal at the Reason office in which he said he felt my questions were "overly tautologous," in the sense of "Needless repetition of the same sense in different words; redundance."
I was, and am, a fan, and got a little stammery at the Great Man sounding perturbed on the other end of the line. I made stumbling attempts to explain my strategy in question writing, but he kept to his rumbling sense of annoyance. I took him at his word, that he was not interested in pursuing the interview, and after 90 seconds or so the conversation ended. His publicist later told me that I'd blown it; that the very fact he called me meant that he was likely open to me steering that very call into the interview I was seeking. (I don't know whether to be impressed or annoyed by how incredibly gracious Vidal was with another troublesome interviewer, Ali G.)
I have failed, I fear, to get across the pleasures of his mind and work entire. He was a serious writer, and as such he wanted most to do, as he quoted the largely forgotten American writer Logan Pearsall Smith, was "to set a chime of words tinkling in the minds of a few fastidious people." In his day, the best-selling Vidal reached more than a few, and he deserves to keep reaching more and more as long as even the shell of the American Republic he studied and chronicled and loved and feuded with stands.
He did great work, he deserves respect, and his views and his acerb and erudite way of expressing them will be missed.