The Later Adventures of Tom Jones by Bob Coleman (Linden/Simon & Schuster: $15.95; 347 pp.)

Writing a sequel to a famous novel is often a thankless task: By performing it, one virtually begs comparison with a writer whose greatness Time has already certified. And Bob Coleman, whose first novel is a sequel to Henry Fielding’s “Tom Jones,” automatically sets himself beside a man who, along with Daniel Defoe and Samuel Richardson, invented the English novel--and of those three, Fielding was the sharpest and most incisive writer. Stiff competition indeed. But despite the odds against it, “The Later Adventures of Tom Jones” emerges in the end as a commendable novel in its own right.

Coleman’s story runs like this: Tom Jones, that foundling upon whom Fortune smiled (to say nothing of a number of women), inherited Paradise Hall from Mr. Allworthy and is now a middle-aged, widowed father of three grown children. Bored and still brooding over the death of his dear Sophia, he decides to leave Sommersetshire on an adventure that entangles him in the brewing insurrection in the American Colonies and tempts his enemies to steal his estate in his absence.

Coleman correctly emulates two qualities that make Fielding important to scholars: his distancing of the reader from the characters (a radical break from the subjective modes of Defoe and Richardson, anticipating 19th-Century novelists like Austen and Dickens) and his whimsical use of the epic tradition (one chapter is called “Containing a Storm as Violent as Any in Homer--and Which None Should Read Who Cannot Swim”). He also makes good use of archaic diction.

But when it comes to imitating the languid, half-stopped rhythm of the period’s prose, Coleman isn’t up to it, and that hurts the reader’s suspension of disbelief: We become painfully aware of a 20th-Century writer trying to write like an 18th-Century writer and failing. Which wouldn’t be so bad, except that his narrator is Henry Fielding come back to us after a 200-year absence. The novel would have been better served if he had shucked the authentic diction and simply written in a contemporary approximation of Fielding’s style (if you are going to pretend that you’re Fielding in the 20th-Century, you might as well write 20th-Century prose).

But this fault seems less important the further one reads, for Coleman has designed a wonderful plot, full of complications and calamities, that keeps us eager for the next chapter. It is, perhaps, not as brilliant as its model (which Coleridge described as one of the three most perfect ever planned), but it is worthy of Fielding’s spirit.

The same goes for Coleman’s large and delightful assortment of characters. As in Fielding, we encounter heroes and heroines who are lovable despite their shortcomings and villains who rouse our righteous anger, people worth laughing and hissing at, crying and cheering for. Coleman retains two characters from the original: Squire Jones himself, and another whose identity is best not revealed in a review. For “Joseph Andrews” fans, he resurrects the spirit of Parson Abraham Adams in the person of his son Hezekiah. He also makes good use of Fielding’s penchant for illustrative names: For instance, Jones’ destructive oldest son is named Hacksem, his evil lawyer called Mr. Sinamore.

In the end, Coleman’s ability to draw from the deepest wells of readerly emotion with his characters distinguishes this novel. One could harp on its faults and note that he lacks Fielding’s considerable talent for comedy and satire, but that would be unfair to a story that, when it ends, inspires sorrow that there is to be no more of it. “The Later Adventures of Tom Jones” may not follow its hallowed model into literary immortality, but it would also be unfair to dwell on that point. Critics and readers have, after all, sung Henry Fielding’s praises for two centuries, Bob Coleman’s for none yet; he is bound to suffer by strict comparison.