The Zen of Fish, by Trevor Corson

This sushi history is neither fish, nor flesh, nor good red herring

This book is an absorbing exploration of the fascinating science and recondite craft of sushi. Trevor Corson's account ranges from Japanese knives ("among the sharpest in the world") and disposable chopsticks (the Japanese get through 25 billion a year), to the reason raw fish is so good to eat ("Fish don't need to fight gravity, so their flesh consists of flakes of muscle held together with only a delicate matrix of collagen") and the risks inherent in eating raw salmon. A 30ft tapeworm extracted from one sushi aficionado can be seen in a Tokyo museum.

Unfortunately, the book is also a deeply tedious account of the Hell's Kitchen-style experiences of a group of trainees in a Los Angeles sushi school. Corson devotes many pages to the spirited striving of Kate, "a 20-year-old Irish-Italian girl with a pierced bellybutton and a nose stud", whose antipathy to the more visceral aspects of fish butchery suggests that she is not naturally suited to the sushi trade.

Kate is used as a vehicle to introduce various piscine mysteries. "What are scales for?" she inquires while struggling ("Dis-gust-ing!") with a tropical yellowtail. "It was a good question," Corson writes, before explaining that they are a form of armour-plating to repel maritime worms. The inclusion of formulaic stuff about the uphill struggle of greenhorn chefs suggests that either the author or publisher had doubts concerning the appeal of an in-depth book about foodstuffs made from raw fish and rice.

This desire to expand the book's audience leads to some jarring gear-changes in what Hollywood (a distinct influence on Corson) would call the book's "narrative arc". Between an explanation of the appeal of flatfish to sushi connoisseurs and the tricky business of perfecting the "wave cut" that enables octopus flesh to stick to rice, we encounter "gorgeous" Alexa Vega, "star of the Spy Kids movies", eating a vegetarian roll made by a trainee.

The problem with this oscillation is that readers beguiled by the travails of the apprentices will find too much about, for example, the prehistory of sushi (which started in Thailand "a bit like a pungent aged cheese"), while the ichthyologically obsessed will skip swathes of text devoted to the Ramsay-style bellowing of the sushi teacher. This could have been one of the great fish books, a masterly exposition of a booming business, but the result of Corson's impressive endeavours is neither fish, nor flesh, nor good red herring.

HarperCollins, £14.99. Order for £13.50 (free p&p) on 0870 079 8897