The author, John Treherene, is a Zoologist and a Fellow of Downing College Cambridge. While on the Galapagos Island of Floreana in the 1980's he heard about an extraordinary series of events, culminating in two disappearances and three deaths in suspiscious circumstances, which had taken place on the island fifty years previously. These events had created a furore in the international press at the time, but been forgotten by the world during the second world war, and were now remembered only by a few elderly islanders.
Out of interest Dr Treherne put together as best he could the story of these extraordinary events and published them in this book, together with his own analysis concerning which of the deaths were accidental and which were murder.
If it had been published as a novel, everyone would have dismissed this story as too strange to be credible.