One of my favorite books of all time. However, I actually think the main character, The Boss, is egotistical and I disagree with his attitude toward the medieval people he meets. Since I suspect Mark Twain himself totally identifies with The Boss, then I suppose I disagree with him as well! The plot is believable, only because it clearly is a delusion. If one accepts that Hank Morgan, a.k.a. The Boss, really went back in time and managed to remember dates of eclipses and knew how to recreate the conveniences of "modern" civilization, then he must surely be a genious! The premise is highly unlikely, and it never occurs to him or the author that the lifestyle of the medieval peoples and the social structure of their society was meant to progress at its own pace. Despite disagreeing with all of it, I really love this book, which surely means Samuel Clemens is the real genius!