"I hope you have enjoyed the story of York and the Lewis and Clark Expedition. When I started writing this book, I had been studying the Corps of Discovery for more than seven years. I always felt like York's story needed further telling. He was such an important part of the expedition, but sadly, so often gets little credit. I was able to find many more books on Sacagawea and Seaman than on York, which made me particularly sad. Most of the story you just read is historically accurate, based on many, many hours of research into the Corps of Discovery in general, and York's part in particular. With so many people tasked by President Jefferson to keep journals, it was a well-documented trip. And now with the power of the internet, those journals are readily accessible to anyone who wants to read them. I used the expression "proceeded on" as often as I did because it was a common phrase in many of those journals. Oftentimes, both Captains and at least one of the Sergeants would comment on something, and add "we proceeded on." It was clearly something that they all thought about often. Where I really took literary license was in my descriptions of York's family and his life after the expedition was completed. There is so much we don't know about that. We do know that he was married before he left to go west, that he moved to St. Louis with Captain Clark two years after the expedition finished; and that Captain Clark took ten years after their return to civilization before finally granting him his freedom. Beyond that, my research only turned up scarce and often contradictory mentions of York for those latter years. So this story is the way I would like to think that his life turned out, but it is highly unlikely that we will ever know for sure. In this book, I hoped to bring honor to York and his role in the expedition - honor that was seriously lacking in his lifetime."