Not many novelists cum creative-writing teachers are as zealous about their second job as Scarlett Thomas. Having written eight novels, and lectured for eight years at the University of Kent, she has developed a fascination with the way that she thinks "beginning writers" go about becoming good ones. This book refines her teaching into a cogent programme – with exercises, charts, the lot. "Once you have read it," she says, "you will, I hope, know how to construct a good sentence, a good metaphor, a good scene, a good plot and a good character."

And actually she does a splendid job. True, there are a lot of venerable nostrums in her advice: show, don't tell; write what you know; keep a taut chain of causation; wince over your adjectives and adverbs. But Thomas explains the reasons for these precepts clearly, with backing quotations from the greats, and shows us plenty of exceptions. She also eschews the self-flagellating ethic of some courses by preaching tolerance for fancy prose style, and exhorts her readers to be ambitious and "ask important questions" with their fiction, an admirable stand.

She offers new things, too, and is particularly good on creativity, where she recommends completing matrixes (not matrices) with details of your life and personality. The idea is that these become reservoirs of material that make it easier for stories to begin to flow. I bet it works. Indeed, again and again, I found myself reading and agreeing with Thomas, however much I blenched at the idea of making novels out of "superobjectives", "thematic questions" and "seed words".

There is a problem, though, and it is serious. I also agree with Thomas's advice to use good clear words, so I'll just come out with it: her book is boring. At least it was to me. This was a surprise because an obsession with the machinery of novels would certainly feature on my personality matrix. Usually it's me who does the boring. The book's chatty style was one factor – 480 pages is a lot of time to spend with prose that's so relentlessly OK. Worse, though, was what the words said. As novelists go, I'm only a junior practitioner next to Thomas, but so much of what she has to say seems rather basic, or well known, or redundant, or obvious in some other way that you have to wonder who this book is for.

For example, having heard that there are plot shapes called "Stranger Comes to Town" and "Rags to Riches", do we also need to read several pages on what happens in them? (You'll never guess.) In a discussion of Stanislavski, we hear that people are driven by complex sequences of motivation. Indeed they are, but if this book is where you found that out I'm worried about your novel. "One of the biggest problems for beginning writers is this need to over-explain," Thomas says, describing fiction. It's true in other areas as well.

Perhaps some absolutely embryonic novelists will see things differently and enjoy the book. But I still question what they'll get from it. The gap between knowing how to do something and being able to, in this area, is wide. Novels are easy to write, but difficult to write skilfully, and skill comes from practice, but practice is difficult to get because bad writing lowers morale: as a reader, I want novelists to suffer in that feedback loop. It's where they learn the idiosyncratic tricks and calibrations that make greatness, from time to time. By comparison, Monkeys With Typewriters feels like an escape hatch. For stuck hobbyists, or just the extremely green, it may well be a reliable guide down one path towards the Shangri-La of adequacy. Excellence, however, and as always, lies just as many years away.

Leo Benedictus is the author of The Afterparty (Vintage)