Robin Robertson has taken the epigram for his fifth collection from the French painter/poet Francis Picabia, who reminds us that "the greatest man is never more than an animal disguised as a god". It's an apt choice for a book that concentrates on the conjunctions between the brutish, the human and the divine. The first poem, based on one of Fra Angelico's Annunciation paintings, dramatises the moment when the Christian God takes human form. There's something sinister about the creature through whose intercession this comes about, who comes from the garden to the loggia where Mary sits on a simple wooden stool and leaves "no shadow, no footprint in the dew". Is he more than human, or less? Like the painting, the poem freezes a single brief moment in which everything changes, linking Fra Angelico's lines of perspective with the event's construction in time: "They hold each other's gaze at the point / of balance: everything streaming / towards this moment, streaming away."

For Mary, her "over-shadowing  by a feathered dark" is something morally uncertain, a matter neither for celebration, in the traditional Christian reading of the scene, nor yet exactly regret. It is simply a fact that, being powerless to change, she must accommodate as best she can: "How will she remember the silence / of that endless moment? [] She will remember the aftersong / because she is only human. / One day / she'll wake with wings, or wake / to find them gone."

The following poem also deals with a "Coming God", but in this case it's Dionysus, in one of several pieces here based on the Dionysiaca of the fourth-century Greek poet Nonnus. Here, rather than reveal himself to humankind, the young Dionysus grows up among goats, deer and bears and forges his own relationship with wild nature. Later in the collection, in "Dionysus in Love"  with its echoes of the temptation of Christ, the fall of Satan and the story of Icarus  the satyr Ampelos's attempt to emulate Dionysus's mastery of wild creatures is bound to end in tears, even for the god "who never wept". And so it does, albeit with the not inconsiderable consolation, for humanity, of the invention of wine, as the dead Ampelos is transfigured into the first vine.

The world of Robertson's poems tends to be one governed by unfathomable and harsh impulses and imperatives, whether they're dealing with mythic characters or those from our own reality. In "1964", a series of vignettes from the poet's childhood, we're confronted by "a fox / nailed to a fence-post: the tricked god / hanging from his wounds"; boys scrap viciously among the graves in the kirkyard; and cats cry in "that dreadful way they have, / like the sound of babies singing / lullabies to other babies".

Whether it's Dionysus's protean transformations or the bodies of the dead being reclaimed by nature, matter is constantly churning into new shapes, decaying and reforming in an endless and inescapable cycle. The sea, in "Corryvreckan", does something similar, with the Hebridean whirlpool's "walls of water, each as tall as a church door, / endlessly breaking on the same point  / each wave swallowing its own form / and returning, re-making itself, chained there / on its own wheel".

Translated into the realm of art, of a humanity that likes to consider itself civilised, these things become dismal indeed. Robertson draws, as he has done previously, on the life of Strindberg in the exuberantly misanthropic "Strindberg in Skovlyst". Here the Swedish playwright, renting rooms in the Danish manor where he will write Miss Julie, finds himself in a human menagerie in which any distinction between human and animal is blurred, at best, and everything is presided over by the house's mad châtelaine: "Like magic, rabbits hop out of coal-scuttles, / turkeys squabble in the bath-tub, eating soap. / With a flourish, she reveals / a litter of white kittens in a drawer / then, shyly, from the front of the sky-blue / off-the-shoulder dress she wears each day, / she pulls a duckling " But for Strindberg, all this is merely so much grist to the artistic mill: "A three-hander, then, with this shambles for a stage: / this home to pestilence, cluster flies, blowflies, men / and women [] my crucible will turn this all to gold. / In my head, when the gales are riding wild, / I steer towards catastrophe / then write about it."

In truth, though, there's not much consolation to be found in art; for the critical intelligence, bound to the knowledge of both an unremittingly Hobbesian reality and the inevitability of its own extinction, perhaps the best to be hoped for is the fate of the lobster in "A Quick Death": "The forecast is for stormy weather [] it's the same for us all in the end  / a short journey: eyes first / into the fire."

Thematically, Hill of Doors is of a piece with Robertson's superb 2010 collection The Wrecking Light, which was shortlisted for the big three prizes (Forward, Costa and TS Eliot). There are similar dreamscapes, abandoned houses, echoes of an extinguished human presence reclaimed by nature, and a similarly flinty beauty to the imagery. It's perhaps a little more uneven than the earlier book, with a couple of poems striking what seems to me an uncertain note, but no doubt it will be in the running for prizes, too, and deservedly so.