Most of the time, we read biographies for no better reason than that their subjects appeal to us. We simply want to know more about Emily Dickinson or Michelangelo or Edison. But now and again a biographer comes along who transmits in-depth scholarship through an ingratiating style, who approaches the writing of a life as an opportunity for self-expression, even for literary distinction. Don’t we return to James Boswell and Lytton Strachey largely for the urbane pleasure of their company?

Certainly I do, just as I eagerly pick up anything by Holmes, best known for his prize-winning biographies of Shelley, Coleridge, and Dr. Johnson’s doomed poet friend Richard Savage. Drawn to artists susceptible to "loneliness and despair," this self-described romantic biographer generates such novelistic excitement that one races through his books as if they were intellectual thrillers. Which, in fact, they are. Not that Holmes (suggestive name) doesn’t do all the usual detective work of research, going through the archives, consulting sources, marshaling his notes. But when he starts to write, the sentences are those of an artist rather than an academic.

Listen to just a bit of his description of the Victorian philosopher John Stuart Mill, an "administrative piston" at the East India Company for 35 years: "Most of his active life was passed at the end of that 100-yard-long gaslit corridor in Leadenhall Street, behind a thick green baize door, in a high bare office smelling of coconut matting and ink and coal dust, inditing the sealed instructions of Imperial administration. He wrote erect at a mahogany lectern, and gazed through windows overlooking a brickyard wall, where a City clock could be heard but not seen. He dressed habitually in a black frockcoat of old-fashioned angular cut, with a black silk necktie pulled tight round a white cotton wing-collar. He was a tall, bony, slightly stooping figure who shook hands stiffly from the shoulder and was prematurely bald at the age of 30. There was that indefinable mineral quality of a dissenting clergyman." Note the factual details, the evocative diction, the gradual coming into focus of a seemingly unappealing figure. "And yet," adds Holmes, "there were nightingales in his story." That romantic image segues into a brief account of the utilitarian thinker’s impassioned, life-altering love for a married woman.

Sidetracks collects a dozen superb "portraits in miniature" (of poet Thomas Chatterton, ghost-story master M. R. James, and photographer Nadar, among others), essays on the nature of biography and the pleasures of living in France, a couple of radio plays, and even a short story about Dr. Johnson’s first cat. Holmes interleaves this admittedly occasional material with headnotes that touch on freelance journalism, life with novelist Rose Tremain, and the nature of his art: "The great thing was simply to summon up for one moment a living breathing shape, to make the dead walk again, to make the reader see a figure and hear a voice."

Though clearly a miscellany despite his efforts to link the various sections, Sidetracks is as enjoyable as any of Holmes’s more sustained works. It’s also a good introduction to his appealing personality. Opening a piece on James Boswell, for example, Holmes provides just the right flourish: "Biography, like love, begins in passionate curiosity."

—Michael Dirda