Analysis of Mr Cassini, by Lloyd Jones.

Through his narrative about a walking tour of Wales, Lloyd Jones confronts issues of memory and imagination, sanity and obsession, and the influence of the mythic past on the national as well as personal present. The character of Duxie, who cannot remember significant portions of his own life, uses his active imagination to fill the gaps left by amnesia. Deciding to travel to meaningful locations, he literally goes step by step to recreate his missing history.
Along the way, the reader is presented with fragments of narrative that may be true or may be his or another character’s inventions. These include vivid images of the captivating yet terrifying, vampire-like predator, Mr. Cassini. Repeatedly criss-crossing Wales, so that the country serves as a subject and not just a backdrop, Duxie and the people he encounters assemble a collective impression of a nation steeped in, and perhaps paralyzed by, the mythic past of King Arthur’s magician, Merlin.
https://books.google.com/books/about/Mr_Cassini.html?id=KNlrDQAAQBAJ