Three years ago I was in the Czech Republic at a place called Duchov researching for a biography of Casanova. The great eighteenth century adventurer spent the last years of his life in the castle of Dux (or Duchov) as librarian to Count Waldstein. It was there that he wrote his Histoire de ma Vie, the masterpiece of autobiography known to the world as the Memoirs of Casanova. Naturally I studied what original Casanova manuscripts remained at the castle, but I also decided to examine all the books in the library dating from Casanova's time. I was looking particularly for volumes which had once belonged to him. It was known that Casanova came to Dux with a substantial library of his own and that these were almost certainly absorbed into the collection at Dux on his death.