ATTEMPTING a sequel calls for a special kind of derring-do. It usually follows a success, its protagonists have obviously struck a chord with the readership (or viewership) and expectations are sky-high.Double the measure all round when the sequel-writer is not the original creator and the work in question is a popular classic. Mrs DeWinter, Susan Hill Long’s follow-up to Rebecca, scrapes by with two stars on amazon.com; Alexandra Ripley’s sappy sequel to Gone with the Wind doesn’t manage even that.

That is not to say, however, that other-author sequels are an inherently bad bet: The Mandala of Sherlock Holmes is just one of the many re-creations of the classic detective to find an enthusiastic public; Mark Winegardner’s The Godfather Returns spent 69 weeks among the top three on the New York Times hardcover bestseller list.

So what makes one sequel score with fans while another misses the mark completely? The answer’s complex, but what is clear is that a faithful echoing of the original’s perceived pluses is no guarantee for a hit. Ellen Feldman starts with an advantage there: the fiesty protagonist of the original work is indubitably dead.

But life must go on for those who survived the terror that claimed Anne Frank and six million other Jews. Peter van Pels — Peter van Daan in The Diary of a Young Girl — heads to the US, with countless other DPs (displaced persons), determined to build a future that has no bearing on the past. He is 20, white, sharp and street-smart, spotting the nascent trend for suburban housing and two-car garages and fathering the baby boom; his will be the hand that rocks America in the mid-20th century.

And for a while it is, as van Pels (‘‘a good American name,’’ the customs officer greets him in New York) accrues all the WASP trappings: a pretty wife, three kids, a thriving construction business, a compliant partner. The country club membership eludes him, because his wife is Jewish, but van Pels has no issues about that.

And then one day, he loses his voice. A battery of doctors can find no reason; finally it is van Pels himself who tracks it down: It was the sight of his all-American wife reading The Diary of a Young Girl and, later, carefully classifying it under ‘fiction’ in their home library.

Not Anne Frank, then, but her enduring work is a character in Feldman’s what-if sequel. The diary — edited and published by her Auschwitz survivor father Otto in 1947 (the English translation followed in 1952) — is also van Pels’ story; in it is the past he has buried in order to build his present; in it lie the ghosts he must confront if he is to be whole again.

Feldman treads a fine line in The Boy...: too easily could the story have slipped into the linear sentimental-healing trap; instead, through the first-person narration, the author widens the ambit to rip apart the true-life American hypocrisy of celebrating a Nazi sympathiser in her theatrical role of Mrs Frank, or portraying Peter’s father as a thief to ‘‘raise’’ the second act.