‘Tom Jones’ in the Flesh : HENRY FIELDING, <i> By Donald Thomas (A Thomas Dunne Book/ St. Martin’s Press: $18.95; 436 pp., illustrated)</i>

Among the most colorful of English novelists, Henry Fielding, author of “Tom Jones” and “Joseph Andrews,” sprawled across the first half of the 18th Century like a wayward Bacchus after a long debauch.

He was lecherous, often drunken, quarrelsome and at times brutally violent. His conversation was coarse, his company lively if argumentative. A thoroughgoing rake with a strong taste for buffoonery, he was at the same time handsome and robust, with an unflagging vitality that allowed him, as a student, to carouse all evening and then study “the most abstruse authors” for the rest of the night.

And, of course, he was a great novelist, one of the handful of writers who shaped English fiction.

Fielding’s most recent biographer--Donald Thomas, professor of English at the University of Wales--is far less interested in Fielding the outsize character than he is in Fielding the public man.

“Few English writers were more involved in the public life of their times than Henry Fielding,” Thomas writes. The targets of his fiction and his journalism were “a corrupt political system of patronage and preferment, (and) a society rotten with petty commercial greed and unprincipled sexual avarice.”

Fielding’s view of the world was a jaundiced one, according to his biographer. Like the Marquis de Sade, to whom Thomas repeatedly compares him, Fielding observed that virtue was usually punished and vice usually rewarded, at least in Hanoverian England. And since the novelist was “seldom far from the public arena of argument and abuse,” he had ample opportunity to observe the meting out of punishments and rewards.

His personal experience was thorny enough to jaundice any man. The son of a down-at-the-heels soldier who beat him and who was only fitfully in funds, the young Fielding was sent to Eton and later to the University of Leiden in Holland, though his stay at both schools was brief. He was rowdy and ungovernable, yet quick to learn. He acquired an appreciation of the classics, and began writing comedies at a very early age.

The need to earn a living drove the young Fielding to write for the London stage, and he enjoyed a brilliant success, pouring out a baker’s dozen of plays in only 2 1/2 years. Yet he invariably outspent his income, and was cursed, like his father before him, with the constant need to borrow money. His creditors hounded him, and at times he was a virtual prisoner in his lodgings, unable to go out except on Sundays when the law prohibited arrests for debt. Family life too brought its sorrows: the early death of his first wife and of several of his children, continued money shortages and Fielding’s own increasingly poor health.

In his 30s, the playwright became a student at the Middle Temple, and, as a junior barrister, had to travel from town to town to attend the provincial courts. Riding was a torment to him, for his years of dissipation aged him prematurely and gout so damaged his circulation and disabled him that during his worst attacks he could not stand without help. Eventually arrested and imprisoned for debt, he languished in prison, surrounded by “darkness and disease, torture and rapacity, crowded bodies and stinking cells.”

Thomas dutifully rehearses Fielding’s literary labors, examining each work in turn. The biographer is neither a panegyrist nor an iconoclast; his approach is to ground each work in its time, place, and circumstances. This is an admirable approach, as far as it goes. Yet readers curious about the inner life of the prodigious Fielding will be disappointed. One cannot help wishing that Thomas had told us more about the sources of Fielding’s phenomenally aggressive drive, the vital force that goaded him to produce such quantities of publishable prose and that spent itself in violence and debauchery.

At times, Thomas tends to view the restless, combative, prickly Fielding through a romantic haze, blurring his sharp edges. His prose is repetitious, and he allows his own rapturous descriptions of the English countryside to carry him away. The narrative bogs down after the first third of the book, and overwritten sentences mar its generally astute literary analysis.

Here is Thomas bidding farewell to his subject: “Before Atropos, daughter of Night, cut the thin-spun thread of life with her shears, the verge of memory held that world of the child’s first summer, the shimmering flats of Wedore, the windbreaks of poplar and willow along the little watercourses, the tide-washed brilliance of a Western sea in the horizon curve of April sky.”

Fielding was very much a man of his era, and Thomas does a thorough and conscientious job of depicting him as such. The scurrility of early Hanoverian England has rarely been surpassed: One famous political cartoon featured a monument raised to George II’s farts, and to pamphleteers, it was always open season on government officials. Obscene abuse, vulgarity (much of it highly amusing) and coarse satire were the order of the day, and Fielding was a master of all these categories of insult.

Fielding also favored what Thomas calls “a stance of moral nihilism,” bleak and curmudgeonly. To him the 1740s were a time when a “leaden gothicism” began to dampen the Augustan spirit, a time of darkness and of the decay of taste. His own personal hopes too grew leaden. The critics by and large disliked his novels, his energy was flagging, and his art was misunderstood and reviled. (One enemy denounced “Tom Jones” as Fielding’s “History of Bastardism, Fornication and Adultery.”)

Yet he took refuge in the comforts of philosophy, and prayed for posthumous fame. His one sure guide in life was the exemplary wisdom of Socrates. “How would Socrates have acted on this occasion?” he asked when sorrows and disappointments closed in.

As for the critics, they were to Fielding nothing more than “little reptiles” whose ephemeral opinions soon would evaporate from public memory. Critical opinion counted for little in the eye of eternity; it was the kind judgment of posterity that Fielding hoped to gain.

“Comfort me by a solemn assurance,” he wrote in “Tom Jones,” “that when the little parlor in which I sit at this instant shall be reduced to a worse furnished box, I shall be read with honor by those who never knew nor saw me, and whom I shall neither know nor see.”

Henry Fielding, wherever you are, take comfort.