They must be putting Viagra in the HRT. First, in her challenging study [i]The Boy[/i], our chief feminist guru Germaine Greer pronounces that it's all right for us crones to drool over the beauty of young men. And now our literary guru has gone a step further, allowing the strapping sons of Priapus to drool over us.

The title of the first of the four novellas that make up this collection is, to say the least, ironic. For the women in question are not so much grandmothers as adored sexual muses:

"He was attentive, demanding, possessive, and when one day he saw her lying on her pillows, love–making just concluded, smoothing down loose ageing skin over her forearms, he let out a cry, clasped her and shouted, 'No, don't, don't, don't even think of it. I won't let you grow old.'"

Any woman will feel cheered and cherished by this delicious fantasy, even though we know it to be a lie, that the characters do not live and breathe and climax, that they exist only for the emblematic purposes of their mischievous creator.

And that is the main fault line running through the collection: the stories are too choked with symbolism to achieve their lofty ambitions. Linked into an uneasy whole, they form a symphony to the grand themes of age and immortality, of relinquishing and yet of passing on. The familiar preoccupations that haunt all of Lessing's work are here in counterpoint: the courage and friendship of women; the vain and painful quest for love; the making of civilisations and then how they break; the savage influence of power and politics and its ability to taint the human heart.

The first movement is simply stated in a life–affirming major key. Two women seal their lifelong friendship by each having an affair with the other's son. Inevitably, having shared their mutual, joyful secret, they make a pact to give up, to allow the boys that have become men to make their own lives. The story is irresistible but the tone disappointing. The pairs of characters — the two women, the two boys, their two wives, the two grandchildren — are forced into a moral symmetry that makes this little more than a fable.

But it does set the tone for the second, slow movement, the story of a mother who gradually comes to the realisation that she must let her beloved child go. A young black woman has a daughter by a white boy whose liberal middle class family is depicted with Lessing's characteristic blend of fascination and envious disapproval. They are blessed with a vivacity and rumbustiousness that eclipses the lives of those around them. Not only do they accept the little girl; they take her over and the mother knows she will be left behind.

In gentle echoes of the first story we encounter the breathtaking beauty of boys on the brink of manhood — and the perilous loveliness of girls. An older women reflects: there is no more dangerous item in the world than a pretty young woman on the loose. Luckily, the older woman thought, when we are girls we don't know that we are like sticks of dynamite or like fireworks in a box too close to a fire.

The boys triumph while beautiful girls are the losers. But the disappointments of lives wasted or compromised are offset in this story by the sense that letting go is also passing on; what stifles one generation may liberate the next.

The most powerful story of the four is the final one, 'A Love Child'. A young World War II soldier becomes convinced he has fathered a child during a brief, passionate encounter while he is en route to India via the Cape. Lessing is at her best here, capturing the danger, the suffering, the appalling conditions and the stench of fear and boredom that accompany war. Again, her theme is the raw beauty and promise of youth, the relationship between the generations. Genes, she hints, are one way to achieve immortality: the other more reliable one is art. Unlikely alliances between young and old, mentors and initiates, are cemented through the passing on of poems and literature.

That this is her real imperative becomes clear in the third, dissonant movement. 'The Reason For It' takes us into more barren Lessing terrain — an earlier civilisation struggling for survival and redemption. The elders, who worked for social harmony and a gradual evolution through education, are dying off, leaving their world in the care of a mindless new generation. Youths are loutish, the atmosphere discordant, incontinence and decay are on the ascendance. Power has got into the treacherous hands of beauty without brains.

Some of the warnings here could be dismissed as familiar railings against the raucous age in which we find ourselves, the belief of our own elders that subtlety and reason are in decline. But there is a shaft of anguish that penetrates more deeply. The civilisation in this story is threatened because the songs and stories have been replaced by cruder models. Children no longer hear them and no longer learn to read.

All literature, in the end, is about itself. Lessing here is laying her own claim to immortality through the immutability of her creations. It is hard not to read these flawed but moving pieces as a collective farewell. They are her [i]Tempest[/i]. But it would be a bleak loss to literature if she were to cast aside her magic rod and end her revels too early.