All writers love the book that allows them to give up their day job. And although Richard Adams’s debut novel, Watership Down, is his most celebrated, it was Shardik, his second, that convinced him to quit the office. Published in 1974, it is a heady piece of fantasy centred on the creation of an animal-based religion, in which a giant bear is the object of worship of a developing human society riven by territorial and ideological dispute. It’s hard to see direct similarities with the work of other writers, although there are echoes of CS Lewis and Tolkien. And big animals were definitely in the air (or sea); Jaws was also published that year.

Shardik had taken Adams three years of evening working to finish, until, as he writes in the introduction to this 40th anniversary edition, “at last a point came when the story was complete and only needed polishing. I knew then that writing was to become my full-time occupation, and I was able to leave the civil service for good”. But Adams’s regard for the book extends beyond the reinforcement of a hoped-for career change. It is, he says, his masterpiece, one that fulfils all his requirements for a good novel: a beginning, middle and end, a hero or heroine, and a villain or, alternatively, “a villainous situation calling for redress”.

The villainous situation – progress that is built on the back of enslavement – is not apparent at the start of this 600-page, multi-sectioned novel, and a lot of complicated things have happened by the time we get to it. We start with a simpler scenario: a hunter who encounters a great big bear in a burning forest, “such a bear as never was, a bear tall as a dwelling-hut, his pelt like a waterfall, his muzzle a wedge across the sky”. Kelderek realises that this is no ordinary bear: returning to his settlement on the river island of Ortelga, he defies the local baron, and refuses to tell his story to anyone but the Tuginda, the head priestess on the neighbouring island of Quiso.

When finally he is brought before her, he confesses his earth-shattering suspicion: that the creature he encountered is a reincarnated Lord Shardik, the mythical beast slain long ago by a slave trader, whose return the inhabitants of Quiso await. Through Shardik, it is believed, God will reveal his secret truth, and his chosen auxiliary vessels are a man and a woman, roles into which Kelderek and the Tuginda quickly slot themselves.

The action is under way: Kelderek and assorted priestesses find the injured Shardik, nurse him back to health and even manage to get rid of the baron. Then, naturally, things begin to go wrong, as Adams expands the plot to introduce territorial disputes, political rivalry and corruption. The Ortelgan people, it transpires, have been driven from the city of Bekla, and many believe that the reappearance of Lord Shardik is a sign to try to regain their lost kingdom. From the outset, men tailor the situation to suit their own purposes. “Shardik has been sent to restore us to Bekla,” says the young nobleman Ta-Kominion, before adding that “the peasants need to know no more than that”.

Shardik comes in pretty handy on a battlefield, and quickly vanquishes the Beklan forces. Indeed, he would scare anybody, with his appearance of an animal “created in hell to torment the damned by its mere presence”, his blood-covered claws and the “streaked, ochreous foam” that froths from his mouth, and his eyes, “the eyes of a mad creature, inhabiting a world of cruelty and pain”. (No wonder this awe-inspiring creature stuck in the mind of Stephen King, who gave the same name to the cyborg bear in the Dark Tower series.)

For Kelderek, Shardik brings mixed fortunes: in the wake of the Ortelgans’ victory, he is installed as a sort of priest-king of Bekla, “a city more marvellous than a mountain made of jewels”; but as the years pass, he becomes increasingly mired in realpolitik and desperate for the incarcerated Shardik to deliver more revelations. In need of funds, he revives the slave trade despite his intrinsic goodness: “We can’t afford to be benevolent and generous,” he argues. It is this plot development that provides Adams with his most intensely felt material; the arrival of the sadistic slave-owner, Genshed, who abuses the children he also trades in, provides the catalyst for Kelderek, portrayed from the very beginning of the book as a protector of children, to come to his moral senses.

Shardik is fantastical to a degree not seen elsewhere in Adams’s work, although he did publish a companion book, Maia, in 1984, and there are mythological elements in Watership Down. Its themes are serious: the power of religion and belief to sway and distort human behaviour is underlined by the fact that Adams never reveals whether Shardik is anything other than an entirely mortal bear; the treatment of slavery and child abuse is similarly considered. Whether the novel’s setting and language function as a distraction – its characters with names such as Zilkron of the Arrows, and its fairytale landscapes – is a matter of personal taste; it is certainly a story told with conviction and creative zest. Those rabbits, though, are unlikely to yield their place as his readers’ favourite characters, despite their creator’s preferences.

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