THE MAID OF BUTTERMERE By Melvyn Bragg Putnam. 414 pp. $19.95

Admirers of Melvyn Bragg's previous works will welcome his latest novel, "The Maid of Buttermere." The scene is the Lake District in northwest England; the historical setting is the early 19th century, a time when Romantic poets such as Coleridge and Wordsworth (who appear briefly in the book) were beginning to make the region an "attraction" for the fashionable world. The plot revolves around a true story: the marriage of a beautiful innkeeper's daughter, the "maid" of the title, to an aristocrat, Col. Alexander Augustus Hope, brother of an earl and member of Parliament. Their marriage in fact became the sensation of England in 1802; Coleridge in his first article on the subject called it the "Romantic Marriage."

At the heart of the Romantic movement of the 18th and 19th centuries lay the value of rustic simplicity in contrast to worldly sophistication. As a literary idea, it can be considered one of the first expressions of the English class struggle. Bragg has written about the class struggle before; here, he gives it a new twist. The "Romantic Marriage" is a sham: Col. Hope is no aristocrat, but as poor as the woman he marries. His name in fact is John Hatfield and he was pretending to fame and grandeur in hopes of marrying a wealthy heiress.

The author has divided the book into two sections -- different in focus and style -- to give added dimension to the Hope/Hatfield character. The first centers around Hope's arrival and plan of attack in the Lake District, whose brooding presence is vividly drawn. Instead of finding the wealthy woman he had wanted to capture, Hope becomes infatuated with the maid of Buttermere, Mary Robinson -- with whom, ironically, as Hatfield, he could have been happy. The scenes of their wooing, marriage and disillusionment are among the most moving in the book. In many ways Hope appears a typical Romantic movement hero: introspective, eloquent, attractive to women, akin to Rochester of "Jane Eyre." To underline Hope's multifaceted character, Bragg uses a style matching the Romantic mood. Rich and powerful, at its best it sweeps the reader along; at other times it causes one to struggle with what Hope calls "incontinent garrulity."

Like Rochester, Hope/Hatfield conceals a darker side of himself, and in the second part of the book the author reveals it. In a series of impressionistic sketches, Bragg moves Hatfield from the Lake District to other parts of England and Wales, and shows what has only been hinted at before -- that Hatfield is a bigamist, a seducer, a forger, an ex-prisoner and possibly involved in murder. Using contemporary newspaper accounts, court records, writings of the Romantic poets, as well as Hatfield's own letters and journals, the author creates a new personality, in a style whose factual austerity fits the miserable life and death of his protagonist.

For readers of historical fiction this novel will have a certain appeal. Basically, however, it is a psychological study, and the historical setting and natural environment are subservient to that goal. Except for Mary Robinson (herself far more complex than the Romantic ideal of the simple rustic girl), the other people in the book are overshadowed by Hope/Hatfield. Sometimes the story line becomes confused. Never made clear, for example, is the role of Newton, the protagonist's accomplice, nor why Hope fears him. How was the original plan to marry for money supposed to have worked? What is the origin of the magnificent dressing case and the coach and horses, with which Hope makes such an impressive entrance into Keswick? The descriptions of Hope/Hatfield's swings of mood are sometimes brilliant (his opening soliloquy on the sands, for example), sometimes excessive.

These may seem small points. But the more the Hope/Hatfield character becomes suspect to the other people in the book, the more the reader is expected to understand him -- and while the brilliance of the writing may sometimes con one into belief, lapses of style and plot arouse more doubts than they dispel.

Bragg has attempted a difficult task, the creation of a split personality, about whom one character says: "{He is} a performer ... happier playing a part than being the man he was ... {and} despite all the dangers -- it is a performance that must go on. He cannot stop it, you see. The part has become the man." In the final analysis one might wish the Hatfield side were more fully fleshed out, and the Hope side slimmed down, to enable them to blend together.

The reviewer is the author of three historical novels: "Ann of Cambray," "Gifts of the Queen" and "A Royal Quest."