This book was bursting with research, but in some ways, this made it disorganized and wandering.  The forward emphasizes that the book is focused on Sarah Graves.  Sometimes, it was helpful to connect general information about pioneers to her, but it felt he had little real information about her.  By mid book, it almost felt he abandonded attempting to focus on her.   I did learn a lot of information about the Donner Party situation, especially in regard to their rescue.