AYELET WALDMAN IS a criminal defence lawyer turned bestselling novelist. She is married to Michael Chabon, another lawyer turned bestselling novelist, becoming engaged to him three weeks after they met on a blind date. They live in California, in a “rambling, brown-shingled house”, with their four children, Sophie, Zeke, Ida-Rose and Abraham, and enjoy — we learn from one of Waldman’s personal essays — a lively sex life.

Into this shimmeringly idyllic set-up, Waldman recently tossed a substantial rock, with the following assertion: “If a good mother is one who loves her child more than anyone else in the world, I am not a good mother. I am in fact a bad mother. I love my husband more than I love my children.”

There was a gratifying hoo-ha and Waldman was summoned to defend herself before the supreme arbiter of contemporary morals, Oprah herself.

None of this can have harmed the publicists’ efforts on behalf of her latest novel, Love and Other Impossible Pursuits, which is narrated by a young lawyer, Emilia, who loves her lawyer husband, Jack, more than the son, four-year-old William, with whom she must share him.

The child, however, is not Emilia’s own, but the son of Jack’s first marriage, to a frigid, controlling, blonde Wasp obstetrician, Carolyn (Emilia and Jack are both Jewish). Nowhere are Carolyn’s controlling tendencies more floridly in evidence than in the transactions between her son, his father and his father’s new wife.

In this interesting inversion of the wicked stepmother story the reader’s sympathy is instantly engaged by Emilia, the more so when we learn that shortly before the narrative begins, Jack and Emilia’s two-day-old daughter, Isabel, has died. With considerable ingenuity Waldman gradually leads us to question her heroine’s engaging readiness to admit her own mistakes, large and small. By the time that we come to recognise that Emilia’s disarming emotional openness conceals a survivor’s ruthless determination to have her own way, we like her too much to be wholly repelled by her flaws.

The relationship between stepmother and stepchild is never likely to be easy, particularly when, as in this case, the stepmother was the instrument of the family break-up and the child bears the burden not merely of his own loss and his father’s guilt, but also of his mother’s outrage at his relationship with the “other woman”. Here the difficulties are compounded by the fact that William is, at least by Emilia’s account , astonishingly unlovable — a puny, pedantic child with bad dandruff and a clutch of food intolerances that Emilia privately regards as figments of his mother’s neurotic imagination.

Partly to make the afternoons on which she and William are thrown together more bearable and partly, perhaps, as covert revenge for the way Carolyn uses William to disrupt her marriage, Emila begins to subvert the restrictions placed upon William. The rebellions are tiny — a failure to use his booster seat in the taxi; a butter-iced strawberry cupcake in defiance of his lactose-free diet — but they establish a complicity based on secrets between stepmother and child that his mother does not share. The deeper message that Emilia draws from these secrets is that, just as she has proved a better wife to Jack than Carolyn did because she is not frigid, so she will be a better mother to William, because she is not angry or neurotic.

The attempted seduction of the child by his stepmother seems appalling. At this dark point, for all her sexy, wisecracking charm and courageous efforts to neutralise her self-pity with irony, Emilia is well on the way to appearing even more unpleasant than her runty stepson and his witch of a mother; so dislikeable that even her sexually enthralled husband is on the point of giving up on her.

But then she plays her trump card, a revelation so harrowing that it engages even Carolyn’s sympathy and the two find themselves sharing “a smile of rueful impatience, tinged with pride” at some cute thing that William has said.

With that smile, the crisis of the narrative is resolved, the ends briskly tied up and the story concludes with a one-sentence paragraph — “William Soule Woolf, my unsought, my fortuitous grace” — beneath which the swelling final chords of the score of the major motion picture that it will undoubtedly become are clearly audible.

If Love and Other Impossible Pursuits had started life as a film, it would have been a straightforward, uplifting account of an upper-middle-class family of essentially well-meaning people struggling to come to terms with the ugly imperfection of family break-up. As writing, however, it is considerably darker than its racy, pacy style suggests. Emilia may appear to come from the same stable as Jo March or Emma Woodhouse, one of those imperfect heroines adored by their creators who earn their happy ending by suffering the consequences of their imperfections. But in fact she does not.

When her redemption comes it arrives from outside herself: the world adjusts to accommodate her, just as she wanted it to, and the reader is left with the interesting, if troubling sense, of understanding Emilia a good deal better than she does herself, and of forgiving her a little less readily.

Extract from Love and Other Impossible Pursuits

The ride up in the elevator is silent, punctuated only by the rattle of William’s sniffles, mucus sucked through his nose and throat with dramatic intensity.

Once we are inside our apartment Jack says again, “What happened?”

William says, “Emilia threw me in the lake,” and then he bursts into tears.

“Don’t be ridiculous,” I snap. Then I explain briefly what happened, how we slipped and he fell into the Meer. How it was an accident. “We were having so much fun,” I say, wincing at the pathetic, pleading tone in my voice. “We were actually having a good time.”

Jack turns away from me and bends down to William. He uses his thumbs to wipe the boy’s tears away. “Let’s get you out of these wet clothes and into a hot bubble bath.” He picks William up and is immediately wrapped in the clutch of the boy’s octopus legs and arms.

“Jack! This is ridiculous! The only reason he’s so upset is because he actually had a good time with me for once. He can’t bear the idea that he had fun with me.”

Jack says nothing.

They are halfway down the hallway when I call out: “Just a minute,”

Jack pauses in the doorway to William’s room.

“What?” he says. His voice is taut, stretched close to breaking.

“Aren’t you going to tell him that he’s over-reacting? Explain that he shouldn’t get so crazy over a little mud and water? We were having fun, Jack! I’m sorry that makes him feel guilty, or whatever, because of Carolyn, but it’s not my fault.”

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