Character - 3/5:
O'Reilly and Dugard take care to ensure the individuals in the story are well-rounded. They consistently relate characters' backstories when first introducing them, and include an appendix at the end to explain what happened to various personalities after the events of the story conclude. These descriptions are more analytical than empathetic, so readers are unlikely to develop strong feelings of love or hatred toward any particular character, but the descriptions and cross references are vivid enough to limit the risk of confusion as characters come and go from the action.
Themes - 2/5:
Despite O'Reilly's reputation as an outspoken pundit, Killing Lincoln is relatively neutral and objective in tone. The narrative does frame Lincoln as a hero and the assassins as villains, but few readers would take issue with such characterization. In general the authors prefer to focus on the events and personalities of the story, with minimal discussion of its overarching moral, social, or historic implications.
Interest - 3/5:
While O'Reilly and Dugard work hard to keep the action moving, readers with no interest in history may still find the details overwhelming. At the same time, serious historians may depreciate the lack of analysis. Overall it's best for readers with a casual to semi-serious interest in American History.
Presentation - 4/5:
Text size is moderate, and the 300 page length should be manageable for most readers. Periodic illustrations supplement important character or setting introductions, but the majority of the book is text only. It's a great choice for readers who do not have much time for reading, because the short chapters make it easy to read in 5-10 minute bursts.
Bottom Line - 16/25:
Read this book if you like history.