Nietzsche is the most inspiring of all modern philosophers excepting Ayn Rand, who used a very different approach for exposing her philosophy (The Fountainhead and Atlas Shrugged). Beyond Good and Evil is often touted as Nietzsche's greatest work, but I like Geneology of Morals ( On the Genealogy of Morals and Ecce Homo) at least as much, since I think it asks some questions that are at least as interesting as these, especially "Meaning of the Aesthetic Ideal". Some people imagine that philosophers are boring, and of course this book, like all important books, does take some work, but I often find myself laughing out loud when reading Nietzsche, since he has a really funny and often unexpected turn of phrase. The important concepts in this book include the difference between slave morality and master morality. Nietzsche tries to help the reader understand that there are no absolutes and that everything can be understood differently from a different point of view. He sees the greatest danger as the mindless, instinctive herd, and warns strongly against it, including especially the flawed and oxymoronic concept of the "common good". Since the rise of the Jacobins, more people have been murdered, starved to death or enslaved for the "common good" than for any other excuse.