By simple extension, an argument might be made that J.D. Salinger, who has steadfastly refused to sell the movie rights to ''The Catcher in the Rye'' or to any of his stories about the Glass family, should be nationalized in the public interest, like the post office. The French Lieutenant's Woman,'' which Karel Reisz, the director, Freddie Francis, the cameraman, Assheton Gorton, the production designer, and the Dorset countryside, have turned into one of the most dazzling looking English movies ever made. I'm not sure it is, nor am I sure that Mr. Pinter's highly touted bold and original approach to Mr. Fowles's novel was really necessary or that it is, in fact, a cinematic equivalent to the original work. As beautiful and entertaining as ''The French Lieutenant's Woman'' is, Mr. Pinter and Mr. Reisz seem not to have achieved that particularly seamless transformation that has occasionally distinguished some film adaptations of the past. This ''stereoscopic vision'' may be what endeared the novel to its initial critics, but to read the book now, approximately 11 years after its publication, as I did, reveals that this is hardly more than a charming gimmick.
All fiction is written with stereoscopic vision.
The only difference between ''The French Lieutenant's Woman'' and most of the others is that Mr. Fowles insists on chatting directly to the reader about literature, politics, medicine and whatnot, often making points that almost any reasonably informed modern reader might be expected to make for himself, without the nudging, much as the modern reader does when reading Jane Austen or Charles Dickens. Which brings up the suspicion that the ''problem'' that Mr. Pinter, remarkable playwright that he is, is supposed to have solved in his free adaptation of the Fowles novel was, actually, no problem at all, or, at least, not a problem that wouldn't have solved itself had Mr. Pinter and Mr. Reisz elected to do a perfectly straightforward dramatization of the mid-Victorian narrative that is the heart of the novel. This tale, which allows Mr. Fowles to discourse at length on the differences between today's society and that of 1867, is about a lowborn English governess, seemingly one of society's victims, who, by hook and crook, achieves emancipation, though at the expense of several people she uses along the way. It's a witty, readable story, fancied up by Mr. Fowles's contemporary observations, by his appearance as himself, the novelist, within the Victorian narrative, and by his pretense of not knowing how to end the tale, and so providing the reader with two endings. This amounts to little more than a game of literary peekaboo, and though Mr. Pinter's efforts to find a cinematic equivalent are, I think, not necessary, they are in some ways more interesting, less coy, anyway, than the original.