Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Nothing new here

There is no new research inherent in this book, simply a meandering assortment of previously-published information. If you know nothing about the Lincoln assassination, it might be okay, but there are far better researched, and better-written books on the subject, notably Michael Kauffman's American Brutus or various books by Ed Steers. Of course, you could always dive down to the level of Bill O'Reilly's version.