In the eighth chapter of The Ring of Truth that links the fall of Marie Antoinette with what was called the Affair of the Diamond Necklace, Wendy Doniger quotes a comment which denies that the queen was a greedy liar: "Not true of course, but when everyone believes a lie, it might as well be the truth." While establishing the pedigree of what today is recognized as fake news, the remark also represents the dizzying tension between truth and falsity that moulds the myths of sex, love and jewellery, particularly rings, through the ages.

The book is not about the ring of power that allows the wearer to rule the world, says Doniger in the Preface. Instead, the rings here give a woman a different kind of power, to show that she is true to her love, or that she is the mother of the son who has been promised inheritance. There is the innocent beloved and the clever wife, with the latter often punished by the husband for her wit by being locked up. But she must prove her cleverness by meeting her husband's challenge that not only will she bear him a son under these circumstances but also prove that the son is his. A story from the Kathasaritsagara, of how the trickster Muladeva is outwitted by his wife, is in this tradition. Doniger retells the tale with her flair for gripping narrative, and gathers multiple other stories from other countries and times to indicate nuances of difference and sameness.

One cluster from Doniger's dazzling array of tales is enough to indicate that the ring, spinning through the ages from hand to hand and from text to text, is anything but the Ring of Truth. The title of the book hints at Doniger's humorously ironic approach. In stories of differing provenance, the ring that a man gives a woman may carry his seal, or otherwise be a marker of his identity. This is replicated by the appearance of the son, who must always look exactly like his father. But the process of proof may be littered with falsehoods, counterfeits, pretences, disguises, bed tricks. No reunion is ever simple. Of Shakespeare's many plots that Doniger refers to, the most astonishing bed trick occurs in All's Well That Ends Well. Does it really end well, she asks, all these stories of forced reunions and coerced love?

Even innocence does not always help. In the multiple retellings of the Siegfried myth from the Thidreks Saga to Ibsen and Wagner, Brünnehilde (picture left) keeps on loving the man who was either Siegfried or Siegfried pretending to be Gunnar. Were there two rings or one? Were they exchanged or taken? Siegfried, who marries Gutrun, Gunnar's sister, either does not care about Brünnehilde, or forgets her under a spell — a recurrent motif. Gutrun's display of Brünnehilde's ring on her own finger leads to tragedy. Why do men keep giving other women rings of the women they have raped or lost?

Men forget; they are usually cads, says Doniger. So the ring of memory that women give them leads to numerous adventures of loss, amnesia, second loves and dubious returns, especially in Western medieval literature. Doniger amusedly describes Kalidas's attempts to turn Dushyanta from a cad to a noble king in his play by introducing into the Shakuntala story from the Mahabharata the device of Durvasa's unheard curse. Here Dushyanta's ring on Shakuntala's finger is lost and then found in a fish, a popular motif that links the sea, memory and identity with the ubiquitous fish of myth and religion. But the greatest irony lies in proving women's sexual faithfulness on the basis of a ring, because that turns on what Doniger calls the "slut assumption": women come by jewels only by lying with men. That is how the tricky Tamara (picture, right) acquires her father-in-law's ring, in a desperate bid to continue his line.

From the ring, Doniger moves on to necklaces, and to diamonds. To indicate the mythic power that jewellery continues to carry, she takes her multi-faceted narrative into the 21st century, although she might have resisted that temptation. But her weighty learning is worn wittily. When she brings her conclusions together in the 11th chapter, she is still trying to fathom how myth triumphs over reason.