This is the book I've started reading lately. It's in the "Great Journeys" series by Penguin Books Ltd. What drew me to the book was the beautiful cover by David Pearson and Victoria Sawdon. The book is pretty interesting, very short, and so far, pretty vague. It's about 147 pages and is De Vaca's letters describing what happened to him and the men he was traveling with from Spain to the new world.
As I said, it's a pretty interesting book, I'll let you know more when I'm finished.
