Here it is worth reflecting on the subject of Clarke's overt homage. The historical Piranesi, an 18th-century engraver, is celebrated for his intricate and oppressive visions of imaginary prisons and his veduta ideate, precise renderings of classical edifices set amid fantastic vistas. Goethe, it is said, was so taken with these that he found the real Rome greatly disappointing. Clarke fuses these themes, seducing us with imaginative grandeur only to sweep that vision away, revealing the monstrosities to which we can not only succumb but wholly surrender ourselves.

The result is a remarkable feat, not just of craft but of reinvention. Far from seeming burdened by her legacy, the Clarke we encounter here might be an unusually gifted newcomer unacquainted with her namesake's work. If there is a strand of continuity in this elegant and singular novel, it is in its central pre-occupation with the nature of fantasy itself. It remains a potent force, but one that can leave us - like Goethe among the ruins - forever disappointed by what is real.

How fantastic to have a bestselling novel with an index right at its heart.