‘A dragon is no idle fancy,’ wrote Tolkien in 1936, but ‘a potent creation of men’s imagination, richer in significance than his barrow is in gold’. The potency has only increased over the last eighty years. Dragons crowd the pages of modern fantasy; no one needs telling that Daenerys, the Mother of Dragons, holds a crucial place in George R R Martin’s Game of Thrones universe.

Tolkien nevertheless also declared that ‘dragons, real dragons … are actually rare’, counting ‘only two that are significant’. One has to say that even back in 1936 his vision was far too narrow. Dragons, as is proved to the hilt by Martin Arnold’s exceptionally wide-ranging and multicultural survey, are in fact ‘a global phenomenon’ and a cross-temporal one as well. They go as far back in time as the Babylonian Epic of Gilgamesh, and they turn up across Eurasia, from Ireland all the way to Japan. But how consistent is the dragon phenomenon? And what on earth can it mean about us?

Most of us could probably agree on the basic features of what Tolkien called ‘the plain pure fairy-story dragon’: flying, reptilian, armoured, fire-breathing, gold-hoarding and man-eating, or rather woman-eating, with a notorious preference for aristocratic or royal virgins. We probably also have in the back of our minds some standard images: the knight, like Spenser’s Redcrosse, advancing into the dragon’s cave behind sword and shield; the mounted warrior, like St George, riding down the dragon with his lance; the naked maiden chained to the rock and hoping for rescue, this last a standing temptation to artists in all ages.

Are these universal features or just cultural preferences? Arnold notes carefully that ‘any attempt to provide any all-purpose description of them is simply not possible’, but on the whole the consistency is more marked than the discrepancies. The Book of Job, for instance, gives us the scales, the fire and the invulnerability. The classical myth of Ladon, set to guard the apples of the Hesperides, agrees on the dragon’s unsleeping watchfulness. Dragons are a very marked feature of Chinese culture, though they are characteristically ‘wise and benevolent’. Nevertheless, even in Western traditions there is a sneaking suspicion that dragons are cleverer than we are. An anonymous Anglo-Saxon poet declared gnomically, ‘dragon must be in barrow, aged, proud in treasure’. Here, the word ‘aged’ has strong connotations of wisdom. Long before Bilbo Baggins, the Norse hero Sigurd found out that it is foolish to bandy words with even a dying dragon.

Surely dragons must have some general if not universal significance. But what can it be? What are the origins of the image? Arnold briskly rules out cultural contact: the dragon is too widespread, too long-lasting for this to be a satisfactory explanation. Is the dragon a kind of composite fear image of the predator, left over from the days when human beings were prey animals, combining ‘the winged raptor, the venomous snake, and the sharp-clawed cat’? Could they have originated – Carl Sagan’s unlikely suggestion – as a genetic memory of dinosaurs, inherited from our mammalian ancestors? In more Freudian style, do dragons represent the id, as knights represent the superego? Or are they actually, as Tolkien suggested (probably without meaning his words absolutely literally), ‘a product of men’s imagination’, that is, something resolutely patriarchal?

The last idea is certainly suggested by all the stories of fathers sacrificing their daughters, as well as the repeated linking of female–dragon and female–serpent relationships (Greek Lamia, biblical Lilith, the story of the Garden of Eden) with the root of all evil. Heroes as different as Perseus and (in Norse saga) Ragnar Hairy-breeches are called in to break up female–serpent relationships, innocent in the case of Andromeda, more suspicious in the case of Ragnar’s eventual bride, Thora. She, it seems, made a pet of her little worm until it grew so large that her father became alarmed. One does not need to be Freud to find significance in this story. It is interesting that the gender of dragons is rarely commented on. Their ferocity may make one assume that they are male, and so a threat to fathers protecting their daughters’ virginity, but their seductive wiliness could be seen as female – and wiliness is a threat to patriarchy as well. Dragons, in a word, are chaotic: they threaten established order. This is true everywhere except, it seems, in China, where dragons came to emblematise ‘dynastic power and authority’, and where, accordingly, stories of bold dragon slayers are non-existent. Possibly this version of the dragon was partly a result of China having been one of the so-called ‘hydraulic civilisations’, where rulers controlled water systems so completely that internal resistance was impossible.

There are other interpretations. It is fairly clear, for instance, that in Beowulf the gold-hoarding dragon represents avarice – the ‘dragon-sickness’, as Tolkien called it in The Hobbit and in his earlier poem ‘The Hoard’, and which he clearly thought was a malaise even more present in his own time than in the far past. In the last few decades, dragons have become images of unchecked power and wrath. The temptation for Daenerys is just to say ‘dracarys’ and turn dragon fire on anyone who resists her, becoming, literally, ‘draconian’. She has to learn to bridle her own reactions, just as she has to chain up her own child-eating dragon offspring.

In modern stories, the dragon increasingly is us, as perhaps he always was. C S Lewis’s Eustace turns into a dragon in Narnia under the influence of gold and greed, while Norse sagas hint at the same metamorphosis. As Daenerys’s monster children show, if you link your mind with dragon minds, the dragon minds will alter you.

Except, of course, when dragons have been made cuddly, children’s special friends, a trend started off by Kenneth Grahame’s ‘Reluctant Dragon’ story of 1898 and now well represented in works such as Julia Donaldson’s Zog and Cressida Cowell’s How to Train Your Dragon series, as well as George R R Martin’s novella Ice Dragon. But perhaps this too is just another insidious draconian temptation. We would all like to have a special friend of immense power to terrify everyone.

Dragons are in the end beyond summary and beyond pigeonholing. Nevertheless, this masterful survey both covers the whole range of the phenomenon and offers suggestion after suggestion as regards interpretation. There is no doubt that some of the greatest works of the modern imagination are dragon-centred, including Ursula K Le Guin’s Earthsea sequence, Michael Swanwick’s Iron Dragon’s Daughter and even Terry Pratchett’s Guards! Guards!, which manages to parody practically every dragon motif of the last thousand years. Any uncertainty about how to visualise dragons is swept aside by a hundred illustrations, taking in old masters, medieval illuminations, films and posters (for instance, of suffragettes facing down the dragon of ‘Indecency’). Tolkien would be pleased to know that we once more live in a great age of dragon invention.