‘A Wilder Shore: The Romantic Odyssey of Fanny and Robert Louis Stevenson’
By Camille Peri
Viking, 480 pages

If biographies seldom seem as deeply satisfying as fiction, as intense and intimate, it is because biographers cannot actually enter a character’s mind and reveal what no one but the character knows, thinks, and feels. On rare occasions this is not entirely so: In “The Making of Sylvia Plath,” for example, I had access to the underlinings and annotations in Plath’s books, and these come close to what she was experiencing as she read.

Biographers try to overcome the gaps in knowledge by projection, by proposing over and over again what the subject “must have felt.” That particular locution fills in a tremendous number of holes, those chasms where the biographer cannot drill down — to use a cant expression — to the innermost depths.

With a “romantic odyssey,” as Camille Peri calls it, involving two romantic figures who had a penchant for romanticizing their own lives, the temptation to join them appears inescapable. As a result, the yield is factitious and the desire to articulate what cannot be accessed becomes cloying and, in the audiobook as performed by Jeanette Illidge, even too cheery.

As Fanny Stevenson abandons her first husband and sets off for Europe with her children, the biographer who would prefer to be a novelist creates a scene: “As she waited at the window and rechecked her trunks she must have felt those dreams pried off and blown away, like the house shingles that bounced and skittered down the road.” The sense of immediacy is exciting — and bogus.  

Who knows what range of emotions Fanny may have experienced as she waited at the window? In fiction the scene would be fine, as the novelist is the authority. In biography, that kind of authority is inauthentic, and yet it is asserted repeatedly. Fanny in a “desolate Nevada wilderness” views from a stagecoach what “must have seemed almost unearthly, with its dry lake-bed and desert seas dotted by sagebrush and squat piñon pines.”

Ms. Peri is an evocative writer, and perhaps that is why so many reviewers have hailed this biography as one of the year’s best. The craving to be right there with Fanny has apparently seduced many readers, who want to be on that romantic adventure as she is on the way to discovering her dream husband: that renowned author of “Treasure Island” and the “Strange Case of Dr Jekyll and Mr Hyde.”

So what is a biographer to do, if not resort to pseudo proximity? Actually, novelists like Ernest Hemingway supply the answer: Harness the power of understatement. A biographer can take charge and simply write: “Fanny saw from the stagecoach almost unearthly dry lake-beds and desert seas,” etc. We don’t need the “seemed” or “must have”; instead we should see what she saw, the powerful materiality of a landscape that did not comport with her romantic quest.

An austere biographer might also cut “unearthly,” though the word can be justified because it portrays the character’s world as perceived by the biographer while preserving the distance a biographer has to maintain between herself and her subject.  

If such sanctions against a biographer seem excessive, bear in mind that the “must haves” proliferate: There is the camp life that “must have cheered Fanny”; “many of the miners must have been there just to be near Fanny”; many “must have fallen in love with her.” Of her first wayward husband, it is said that “her righteous anger must have melted into grief and regret.” It is no different with the second famous husband in this faux intimate sentence: “Louis must have felt that Fanny had found a good form for her writing.”

Dozens of passages could be quoted that paper over gaps with suppositions that speak to a yearning to know more than a biography can actually deliver, thereby diminishing the power of what cannot be known. 

Several times Ms. Peri uses the phrase “one can imagine.” Now, that works, because that phrase respects the divide between fact and fiction, and the desire to bridge the void that separates them. 

Ms. Peri writes with considerable verve about Fanny and the difference she made in Robert Louis Stevenson’s life, which is all the more reason why the biographer did not have to egg it.

Mr. Rollyson is the author of “Biography: A User’s Guide.”