"Human, All Too Human: A Book for Free Spirits" by Friedrich Wilhelm Nietzsche is a philosophical work published in 1878. Breaking from his earlier essay style, Nietzsche employs short aphorisms to examine metaphysics, morality, religion, and human nature. Written during his break with composer Richard Wagner and originally dedicated to Voltaire, this collection marks Nietzsche's turn toward French Enlightenment thinking and the aphoristic style that would define his later philosophy. The work challenges conventional Christian morality while exploring the origins of moral feelings and metaphysical thought.
Wikipedia page about this book: en.wikipedia.org/wiki/Human,_All_Too_Human