In the present time, he buys an old book by a long-forgotten 1920s author about those times from one of the famous Parisian Bouquinistes, the second-hand booksellers which line the Seine, and finds he’s one of the characters.
The Bouquinistes sell more than just old books but tourist guides, newspapers and magazines, and other curios, and as Edinburgh wrestles with the problem of what to do about the magnificent but increasingly desolate Princes Street, I wonder if Bouquinistes aren’t part of the answer.
There doesn’t seem to be much of an argument that the days of retail dominance on the north side are over and the shops are likely to be replaced by cafes and restaurants with hotels above.
But even when the tourists return in numbers, there needs to be a lot more to Edinburgh’s showcase street than just one place to have a coffee after another.
Despite many critics, the Christmas Market and its stalls are popular and unquestionably bring life to the south side which between Waverley Bridge and the Mound is essentially one long bus-stop with a very nice view.
But from The Mound to Lothian Road, the pavement is quieter, the bus-stops more spaced out, and between the memorial benches there are a few gaps where some unobtrusive Bouquinistes could operate to bring something new to the street without changing its character.
Edinburgh has a strong tradition of second-hand book sellers and, with Walter Scott looking over it all, a literary heritage as strong as that of Paris, why not?
It’s maybe a linguistic coincidence, but Bouquinistes doesn’t sound so different from Luckenbooths, Edinburgh’s unique but long-gone High Street tenements which had fold-down wooden fronts at street level which by day became shops from where the occupiers could trade.
So Edinburgh has a tradition of fold-away wooden stalls, and a tradition of book publishing and selling second to none. We have an international book festival, a poetry library, was the founding city in the Unesco Cities of Literature network, and the main railway station is the only one in the world named after a book.
And we have a historic street as scenic as the banks of the Seine, crying out for rejuvenation in a sensitive and, as befits another great Edinburgh tradition, understated way.
So if bratwurst, gluhwein and wooden Ruritanian soldiers can be flogged from log cabins in Princes Street Gardens, why not good-quality books from well-run stalls, maybe in partnership with existing traders?
There is obviously a slim chance of Owen Wilson or Carla Bruni browsing around to sweep you off your feet, and none of finding that dusty little tome which features an episode from your time travels, but you can dream. Maybe even the Cockburn Association would approve, or is that a fantasy too far?
In troubled times, anything with the promise of bringing a little magic to the city, even as mighty a setting as Princes Street, would surely be no bad thing.