Kavan's last and best-known novel has provoked and defied classification more than any of her other works. Letters between Kavan and her publisher Peter Owen reveal that she was unsurprised, even flattered, by a reader's report describing Ice (1967) as ‘a mixture of Kafka and The Avengers’ and the novel revels in the tropes of popular entertainment without relinquishing its status as ‘high’ literature. Its non-linear, illdefined and fantastical plot allows its three principal characters to act out scenarios borrowed from romance, porn, spy drama, action-adventure, gothic fantasy and sci-fi; but the novel's subtle misalignment of genres disturbs moral certainties, depicting a happy ending that might be a murderous abduction, a heroine who gets eaten by a dragon and a hero who longs to break her bones. This hybridity of genre has contributed to many critical assessments of the novel as being without parallel – Brian Aldiss claimed that ‘Ice is unique’, Doris Lessing agreed that there is ‘nothing else like it’ and Jonathan Lethem affirms that ‘Ice stands alone’. But Leigh Wilson has observed how even laudatory assessments of Kavan's ‘literary isolation’ have been inflected by assumptions about women's writing, noting that ‘[i]f these critics have rooted the worth of Kavan's writing in a supposed innocence of literary debate and of its provocation to conscious practice, the gender politics of this are not hard to spot’.

Although Ice is often read in isolation, the novel was the culmination of Kavan's mid-century experimental writing career, epitomising the tropes and thematic preoccupations of her early Helen Ferguson novels, continuing the stylistic experiment she embarked upon when she began writing as Anna Kavan, and maintaining the radical politics she developed in the early 1940s. Augmenting her familiar tropes of unreliable narrator, unstable reality, nameless protagonists and temporal impossibility, the novel reflects her ongoing experiment with representations of reality while incorporating elements of the popular and counterculture of the late 1960s.