MORE LETTERS OF OSCAR WILDE. Edited by Rupert Hart-Davis. Vanguard Press. 215 pp. $14.95.

EVERY BIOGRAPHER, or editor of a "definitive" volume of letters, worries that publication paradoxically will set in motion the release of documents which eluded him despite all his earlier efforts. Worse, still, that the new material will render his book instantly obsolete.

Since Rupert Hart-Davis' magisterial Letters of Oscar Wilde in 1962, a trickle of unpublished letters has been emerging, enough of them now for Sir Rupert to collect into an annotated companion volume, using the nine divisions into which the massive original was organized. In some ways, then, the sequel suggests an abridgment of the earlier book. Although few of the 182 letters overlap or duplicate (18 offer better texts than before), there are no surprising new revelations. What we now have only expands slightly what we already knew about Wilde's friends and enemies, transactions and predilections.

Biographically intriguing are the additional evidences of Wilde's early efforts, by whatever means, to promote his reputation, and get his writings published, praised and produced. No fawning seemed beneath him, no flattering sufficiently flagrant, no name-dropping too unseemly. To E.S. Piggott, the Lord Chamberlain's Examiner of Plays -- the stage censor in that timid system which survived until 1968 -- Wilde explained in 1880 that the literary merit of his first play was "very slight," yet in a theatrical tradition that emphasized acting "perhaps the best test of a good play is that it should not read well." If his tongue remained in his cheek when writing to the man whom Bernard Shaw called "a walking compendium of vulgar insular prejudice," one wonders further abut Oscar's mixture of toadying and candor in his confession to Piggott, "I am working at dramatic art because it's the democratic art, and I want fame, so any suggestion, any helpful advice, your experience and very brilliant critical powers can give me I shall thank you very much for." Piggott's only brilliance was in sniffing out sexual innuendo, sometimes where none was intended, and in delaying by a generation the sophistication of the English stage.

If there were a chance of production, Wilde would call a hack melodramatist a "distinguished artist," and would find other writers "exquisite" and "delightful" if there were any likelihood that they might review one of his books, or contribute to a woman's magazine he edited in the middle 1880s. Such practices hardly make him unique in the politics of publishing and playwriting, but they contrast strikingly with the lordly manner of the successful Wilde in the years just preceding his fall.

To the now-unknown editor of a paper in which Oscar Fingal O'Flahertie Wills Wilde was misnamed, he would write in the heady year of 1892 that although John was an "admirable" name, it was not his. "It was the name of the most charming of all the Disciples, the one who did not write the Fourth Gospel. It was the name of the most perfect of all the English poets of his century, as it was of the greatest English poet of all the centuries. Popes and Princes, wicked or wonderful, have been called John. John has been the name of several eminent journalists and criminals. But John is not amongst the many delightful names given to me at my baptism." And, flush with money and fame, he could help out Scottish poet and political radical John Barlas financially, explaining large-mindedly, "We poets and dreamers are all brothers. . . . We will have many days of song and joy together when the spring comes."

FOR WILDE, winter followed spring. The volume's additional letters from Holloway and Reading prisons in 1895 and after re-emphasize the tragedy and pathos of Wilde's trials and their aftermath. Puffed up with the arrogance of what had become more notoriety than fame, he had sued the feisty Marquess of Queensberry for libel in full realization that the charges of sodomy were accurate. What Wilde had not realized was that just as he could buy boys, Queensberry could buy witnesses. Wilde's letters from prison to his attorneys and to others involved in his personal and professional disgrace add details to what has been known about the loss of his wife and of the custody of his young sons, and about his bankruptcy. Until hubris abruptly closed his career, we learn from a prison letter, Wilde was making more money from a single week's run of The Importance of Being Earnest than he would earn in all the five years that were left to him.

The post-prison letters, like the others meticulously and informatively annotated to mesh with the earlier volume, are largely from Paris. They document the sleazy slide into poverty, illness, loneliness and self-pity; only infrequently is there a meteor burst recalling the Oscar of halcyon days. "In art alone is the consolation for the artist," he told actress Ada Rehan in June 1899, but except for his "Ballad of Reading Gaol," he was beyond such consolation himself. The last letter finds him trying to collect from Frank Harris for a plot he had concocted and sold (to several people) in lieu of attempting a play himself. From bed, two months before the end, he pleaded, having offered physicians post-dated checks, "I wanted money to save my life." But he was past saving, and Harris knew.

Will more letters of Wilde now turn up? As I write this, the newest catalogue has arrived from the auction rooms of Christie's in London. One item is a letter to barrister and poet Ernest Radford which appears neither in the earlier volume nor the present one. "I have," Oscar claims in it, "a great dislike of letter- writing."