But his thoughts were all tangled. Rougetel’s story hardly seemed possible. Dyer would have found so much of it difficult to believe if he hadn’t known what Rougetel was capable of.

He wondered about ‘crashing points’. There was Rougetel’s grief after the death of his parents. Had there been other crises? If so, they didn’t feature in his ‘Ladybird’ autobiography.

Dyer took in that Rougetel had passed his twenties and thirties abroad. He had not returned to Latin America. He avoided big cities. All the time that Dyer had worked as a journalist in Rio, Rougetel’s incessant reading was guiding him, in intense bursts of travel, to oblique parts. In book-lined rooms – dusty, deserted – he had steadily augmented his knowledge.

At Dyer’s encouragement, Rougetel traced a map with his forefinger on the tablecloth, moving between places where he had halted in order to study. Djibouti, Ceuta, Niamey, Al-Ula, Tromsø, Royal George, Akureyri, Darovoye, Jotogh, Sihanoukville.

But he hadn’t always stayed abroad. For more than twenty years he had been in England, and for the past two years in Oxford. His new focus of interest, what had brought him back here, was the human brain, and the differing world views of the left and the right hemispheres. He had been inspired by a 608-page book, the fruit of two decades of research, written by a Prize Fellow of All Souls, a scholar in English Literature who had returned to the college to retrain in medicine.

Excited, Rougetel unfastened the straps of his backpack and brandished the thumbed volume for Dyer to see. It looked waterlogged, as if he had dropped it in the Cherwell – until Dyer realised why the pages appeared so bulged-out and yellow: because of all the post-it notes that Rougetel had inserted.

Rougetel had almost finished digesting the book, the implications of which he found inordinately interesting. He had obtained a Reader card for the Bodleian, and had used the library for his background reading, steadily making his way through the author’s bibliography. In a day or so, he would be leaving Oxford.

He glanced across at Dyer, who was still looking at the yellow markers, and gave him a sympathetic smile. ‘It’s lucky we bumped into each other. Next week, I might not have been here.’

Mutely, Dyer watched him tuck the book back. All these months, he and Rougetel had been living in the same city. How many times had Dyer stepped past him?

A line of Horace came to Dyer. Never be amazed by anything.

Chapter Thirty-nine